Add m-esr52 at 52.6.0

1 files changed, 1491 insertions, 0 deletions

diff --git a/image/test/gtest/TestSurfaceSink.cpp b/image/test/gtest/TestSurfaceSink.cpp
new file mode 100644
index 000000000..ccf9be3ec
--- /dev/null
+++ b/image/test/gtest/TestSurfaceSink.cpp
@@ -0,0 +1,1491 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "mozilla/gfx/2D.h"
+#include "Common.h"
+#include "Decoder.h"
+#include "DecoderFactory.h"
+#include "SourceBuffer.h"
+#include "SurfacePipe.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::image;
+
+enum class Orient
+{
+  NORMAL,
+  FLIP_VERTICALLY
+};
+
+template <Orient Orientation, typename Func> void
+WithSurfaceSink(Func aFunc)
+{
+  RefPtr<Decoder> decoder = CreateTrivialDecoder();
+  ASSERT_TRUE(decoder != nullptr);
+
+  const bool flipVertically = Orientation == Orient::FLIP_VERTICALLY;
+
+  WithFilterPipeline(decoder, Forward<Func>(aFunc),
+                     SurfaceConfig { decoder, 0, IntSize(100, 100),
+                                     SurfaceFormat::B8G8R8A8, flipVertically });
+}
+
+template <typename Func> void
+WithPalettedSurfaceSink(const IntRect& aFrameRect, Func aFunc)
+{
+  RefPtr<Decoder> decoder = CreateTrivialDecoder();
+  ASSERT_TRUE(decoder != nullptr);
+
+  WithFilterPipeline(decoder, Forward<Func>(aFunc),
+                     PalettedSurfaceConfig { decoder, 0, IntSize(100, 100),
+                                             aFrameRect, SurfaceFormat::B8G8R8A8,
+                                             8, false });
+}
+
+void
+ResetForNextPass(SurfaceFilter* aSink)
+{
+  aSink->ResetToFirstRow();
+  EXPECT_FALSE(aSink->IsSurfaceFinished());
+  Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+}
+
+template <typename WriteFunc, typename CheckFunc> void
+DoCheckIterativeWrite(SurfaceFilter* aSink,
+                      WriteFunc aWriteFunc,
+                      CheckFunc aCheckFunc)
+{
+  // Write the buffer to successive rows until every row of the surface
+  // has been written.
+  uint32_t row = 0;
+  WriteState result = WriteState::NEED_MORE_DATA;
+  while (result == WriteState::NEED_MORE_DATA) {
+    result = aWriteFunc(row);
+    ++row;
+  }
+  EXPECT_EQ(WriteState::FINISHED, result);
+  EXPECT_EQ(100u, row);
+
+  AssertCorrectPipelineFinalState(aSink,
+                                  IntRect(0, 0, 100, 100),
+                                  IntRect(0, 0, 100, 100));
+
+  // Check that the generated image is correct.
+  aCheckFunc();
+}
+
+template <typename WriteFunc> void
+CheckIterativeWrite(Decoder* aDecoder,
+                    SurfaceSink* aSink,
+                    const IntRect& aOutputRect,
+                    WriteFunc aWriteFunc)
+{
+  // Ignore the row passed to WriteFunc, since no callers use it.
+  auto writeFunc = [&](uint32_t) {
+    return aWriteFunc();
+  };
+
+  DoCheckIterativeWrite(aSink, writeFunc, [&]{
+    CheckGeneratedImage(aDecoder, aOutputRect);
+  });
+}
+
+template <typename WriteFunc> void
+CheckPalettedIterativeWrite(Decoder* aDecoder,
+                            PalettedSurfaceSink* aSink,
+                            const IntRect& aOutputRect,
+                            WriteFunc aWriteFunc)
+{
+  // Ignore the row passed to WriteFunc, since no callers use it.
+  auto writeFunc = [&](uint32_t) {
+    return aWriteFunc();
+  };
+
+  DoCheckIterativeWrite(aSink, writeFunc, [&]{
+    CheckGeneratedPalettedImage(aDecoder, aOutputRect);
+  });
+}
+
+TEST(ImageSurfaceSink, NullSurfaceSink)
+{
+  // Create the NullSurfaceSink.
+  NullSurfaceSink sink;
+  nsresult rv = sink.Configure(NullSurfaceConfig { });
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  EXPECT_TRUE(!sink.IsValidPalettedPipe());
+
+  // Ensure that we can't write anything.
+  bool gotCalled = false;
+  auto result = sink.WritePixels<uint32_t>([&]() {
+    gotCalled = true;
+    return AsVariant(BGRAColor::Green().AsPixel());
+  });
+  EXPECT_FALSE(gotCalled);
+  EXPECT_EQ(WriteState::FINISHED, result);
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  Maybe<SurfaceInvalidRect> invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+
+  uint32_t source = BGRAColor::Red().AsPixel();
+  result = sink.WriteBuffer(&source);
+  EXPECT_EQ(WriteState::FINISHED, result);
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+
+  result = sink.WriteBuffer(&source, 0, 1);
+  EXPECT_EQ(WriteState::FINISHED, result);
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+
+  result = sink.WriteEmptyRow();
+  EXPECT_EQ(WriteState::FINISHED, result);
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+
+  result = sink.WriteUnsafeComputedRow<uint32_t>([&](uint32_t* aRow,
+                                                     uint32_t aLength) {
+    gotCalled = true;
+    for (uint32_t col = 0; col < aLength; ++col, ++aRow) {
+      *aRow = BGRAColor::Red().AsPixel();
+    }
+  });
+  EXPECT_FALSE(gotCalled);
+  EXPECT_EQ(WriteState::FINISHED, result);
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+
+  // Attempt to advance to the next row and make sure nothing changes.
+  sink.AdvanceRow();
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+
+  // Attempt to advance to the next pass and make sure nothing changes.
+  sink.ResetToFirstRow();
+  EXPECT_TRUE(sink.IsSurfaceFinished());
+  invalidRect = sink.TakeInvalidRect();
+  EXPECT_TRUE(invalidRect.isNothing());
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkInitialization)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Check initial state.
+    EXPECT_FALSE(aSink->IsSurfaceFinished());
+    Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+    EXPECT_TRUE(invalidRect.isNothing());
+
+    // Check that the surface is zero-initialized. We verify this by calling
+    // CheckGeneratedImage() and telling it that we didn't write to the surface
+    // anyway (i.e., we wrote to the empty rect); it will then expect the entire
+    // surface to be transparent, which is what it should be if it was
+    // zero-initialied.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 0, 0));
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWritePixels)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    CheckWritePixels(aDecoder, aSink);
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWritePixelsFinish)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Write nothing into the surface; just finish immediately.
+    uint32_t count = 0;
+    auto result = aSink->WritePixels<uint32_t>([&]() {
+      count++;
+      return AsVariant(WriteState::FINISHED);
+    });
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(1u, count);
+
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixels<uint32_t>([&]() {
+      count++;
+      return AsVariant(BGRAColor::Red().AsPixel());
+    });
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is correct.
+    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+    EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Transparent()));
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWritePixelsEarlyExit)
+{
+  auto checkEarlyExit =
+    [](Decoder* aDecoder, SurfaceSink* aSink, WriteState aState) {
+    // Write half a row of green pixels and then exit early with |aState|. If
+    // the lambda keeps getting called, we'll write red pixels, which will cause
+    // the test to fail.
+    uint32_t count = 0;
+    auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+      if (count == 50) {
+        return AsVariant(aState);
+      }
+      return count++ < 50 ? AsVariant(BGRAColor::Green().AsPixel())
+                          : AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(aState, result);
+    EXPECT_EQ(50u, count);
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 50, 1));
+
+    if (aState != WriteState::FINISHED) {
+      // We should still be able to write more at this point.
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Verify that we can resume writing. We'll finish up the same row.
+      count = 0;
+      result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 50) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+      CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 1));
+
+      return;
+    }
+
+    // We should've finished the surface at this point.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixels<uint32_t>([&]{
+      count++;
+      return AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 50, 1));
+  };
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::NEED_MORE_DATA);
+  });
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FAILURE);
+  });
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FINISHED);
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWritePixelsToRow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Write the first 99 rows of our 100x100 surface and verify that even
+    // though our lambda will yield pixels forever, only one row is written per
+    // call to WritePixelsToRow().
+    for (int row = 0; row < 99; ++row) {
+      uint32_t count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint32_t>([&]{
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(100u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mOutputSpaceRect);
+
+      CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, row + 1));
+    }
+
+    // Write the final line, which should finish the surface.
+    uint32_t count = 0;
+    WriteState result = aSink->WritePixelsToRow<uint32_t>([&]{
+      ++count;
+      return AsVariant(BGRAColor::Green().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(100u, count);
+
+    // Note that the final invalid rect we expect here is only the last row;
+    // that's because we called TakeInvalidRect() repeatedly in the loop above.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 99, 100, 1),
+                                    IntRect(0, 99, 100, 1));
+
+    // Check that the generated image is correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint32_t>([&]{
+      count++;
+      return AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 100));
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWritePixelsToRowEarlyExit)
+{
+  auto checkEarlyExit =
+    [](Decoder* aDecoder, SurfaceSink* aSink, WriteState aState) {
+    // Write half a row of green pixels and then exit early with |aState|. If
+    // the lambda keeps getting called, we'll write red pixels, which will cause
+    // the test to fail.
+    uint32_t count = 0;
+    auto result = aSink->WritePixelsToRow<uint32_t>([&]() -> NextPixel<uint32_t> {
+      if (count == 50) {
+        return AsVariant(aState);
+      }
+      return count++ < 50 ? AsVariant(BGRAColor::Green().AsPixel())
+                          : AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(aState, result);
+    EXPECT_EQ(50u, count);
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 50, 1));
+
+    if (aState != WriteState::FINISHED) {
+      // We should still be able to write more at this point.
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Verify that we can resume the same row and still stop at the end.
+      count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint32_t>([&]{
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+      CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 1));
+
+      return;
+    }
+
+    // We should've finished the surface at this point.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint32_t>([&]{
+      count++;
+      return AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 50, 1));
+  };
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::NEED_MORE_DATA);
+  });
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FAILURE);
+  });
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FINISHED);
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteBuffer)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Create a green buffer the same size as one row of the surface (which is 100x100),
+    // containing 60 pixels of green in the middle and 20 transparent pixels on
+    // either side.
+    uint32_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = 20 <= i && i < 80 ? BGRAColor::Green().AsPixel()
+                                    : BGRAColor::Transparent().AsPixel();
+    }
+
+    // Write the buffer to every row of the surface and check that the generated
+    // image is correct.
+    CheckIterativeWrite(aDecoder, aSink, IntRect(20, 0, 60, 100), [&]{
+      return aSink->WriteBuffer(buffer);
+    });
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteBufferPartialRow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Create a buffer the same size as one row of the surface, containing all
+    // green pixels.
+    uint32_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = BGRAColor::Green().AsPixel();
+    }
+
+    // Write the buffer to the middle 60 pixels of every row of the surface and
+    // check that the generated image is correct.
+    CheckIterativeWrite(aDecoder, aSink, IntRect(20, 0, 60, 100), [&]{
+      return aSink->WriteBuffer(buffer, 20, 60);
+    });
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteBufferPartialRowStartColOverflow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Create a buffer the same size as one row of the surface, containing all
+    // green pixels.
+    uint32_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = BGRAColor::Green().AsPixel();
+    }
+
+    {
+      // Write the buffer to successive rows until every row of the surface
+      // has been written. We place the start column beyond the end of the row,
+      // which will prevent us from writing anything, so we check that the
+      // generated image is entirely transparent.
+      CheckIterativeWrite(aDecoder, aSink, IntRect(0, 0, 0, 0), [&]{
+        return aSink->WriteBuffer(buffer, 100, 100);
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Write the buffer to successive rows until every row of the surface
+      // has been written. We use column 50 as the start column, but we still
+      // write the buffer, which means we overflow the right edge of the surface
+      // by 50 pixels. We check that the left half of the generated image is
+      // transparent and the right half is green.
+      CheckIterativeWrite(aDecoder, aSink, IntRect(50, 0, 50, 100), [&]{
+        return aSink->WriteBuffer(buffer, 50, 100);
+      });
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteBufferPartialRowBufferOverflow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Create a buffer twice as large as a row of the surface. The first half
+    // (which is as large as a row of the image) will contain green pixels,
+    // while the second half will contain red pixels.
+    uint32_t buffer[200];
+    for (int i = 0; i < 200; ++i) {
+      buffer[i] = i < 100 ? BGRAColor::Green().AsPixel()
+                          : BGRAColor::Red().AsPixel();
+    }
+
+    {
+      // Write the buffer to successive rows until every row of the surface has
+      // been written. The buffer extends 100 pixels to the right of a row of
+      // the surface, but bounds checking will prevent us from overflowing the
+      // buffer. We check that the generated image is entirely green since the
+      // pixels on the right side of the buffer shouldn't have been written to
+      // the surface.
+      CheckIterativeWrite(aDecoder, aSink, IntRect(0, 0, 100, 100), [&]{
+        return aSink->WriteBuffer(buffer, 0, 200);
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Write from the buffer to the middle of each row of the surface. That
+      // means that the left side of each row should be transparent, since we
+      // didn't write anything there. A buffer overflow would cause us to write
+      // buffer contents into the left side of each row. We check that the
+      // generated image is transparent on the left side and green on the right.
+      CheckIterativeWrite(aDecoder, aSink, IntRect(50, 0, 50, 100), [&]{
+        return aSink->WriteBuffer(buffer, 50, 200);
+      });
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteBufferFromNullSource)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Calling WriteBuffer() with a null pointer should fail without making any
+    // changes to the surface.
+    uint32_t* nullBuffer = nullptr;
+    WriteState result = aSink->WriteBuffer(nullBuffer);
+
+    EXPECT_EQ(WriteState::FAILURE, result);
+    EXPECT_FALSE(aSink->IsSurfaceFinished());
+    Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+    EXPECT_TRUE(invalidRect.isNothing());
+
+    // Check that nothing got written to the surface.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 0, 0));
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteEmptyRow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    {
+      // Write an empty row to each row of the surface. We check that the
+      // generated image is entirely transparent.
+      CheckIterativeWrite(aDecoder, aSink, IntRect(0, 0, 0, 0), [&]{
+        return aSink->WriteEmptyRow();
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Write a partial row before we begin calling WriteEmptyRow(). We check
+      // that the generated image is entirely transparent, which is to be
+      // expected since WriteEmptyRow() overwrites the current row even if some
+      // data has already been written to it.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 50) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      CheckIterativeWrite(aDecoder, aSink, IntRect(0, 0, 0, 0), [&]{
+        return aSink->WriteEmptyRow();
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Create a buffer the same size as one row of the surface, containing all
+      // green pixels.
+      uint32_t buffer[100];
+      for (int i = 0; i < 100; ++i) {
+        buffer[i] = BGRAColor::Green().AsPixel();
+      }
+
+      // Write an empty row to the middle 60 rows of the surface. The first 20
+      // and last 20 rows will be green. (We need to use DoCheckIterativeWrite()
+      // here because we need a custom function to check the output, since it
+      // can't be described by a simple rect.)
+      auto writeFunc = [&](uint32_t aRow) {
+        if (aRow < 20 || aRow >= 80) {
+          return aSink->WriteBuffer(buffer);
+        } else {
+          return aSink->WriteEmptyRow();
+        }
+      };
+
+      auto checkFunc = [&]{
+        RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+        RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+
+        EXPECT_TRUE(RowsAreSolidColor(surface, 0, 20, BGRAColor::Green()));
+        EXPECT_TRUE(RowsAreSolidColor(surface, 20, 60, BGRAColor::Transparent()));
+        EXPECT_TRUE(RowsAreSolidColor(surface, 80, 20, BGRAColor::Green()));
+      };
+
+      DoCheckIterativeWrite(aSink, writeFunc, checkFunc);
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWriteUnsafeComputedRow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Create a green buffer the same size as one row of the surface.
+    uint32_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = BGRAColor::Green().AsPixel();
+    }
+
+    // Write the buffer to successive rows until every row of the surface
+    // has been written. We only write to the right half of each row, so we
+    // check that the left side of the generated image is transparent and the
+    // right side is green.
+    CheckIterativeWrite(aDecoder, aSink, IntRect(50, 0, 50, 100), [&]{
+      return aSink->WriteUnsafeComputedRow<uint32_t>([&](uint32_t* aRow,
+                                                         uint32_t aLength) {
+        EXPECT_EQ(100u, aLength );
+        memcpy(aRow + 50, buffer, 50 * sizeof(uint32_t));
+      });
+    });
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkProgressivePasses)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    {
+      // Fill the image with a first pass of red.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() {
+        ++count;
+        return AsVariant(BGRAColor::Red().AsPixel());
+      });
+      EXPECT_EQ(WriteState::FINISHED, result);
+      EXPECT_EQ(100u * 100u, count);
+
+      AssertCorrectPipelineFinalState(aSink,
+                                      IntRect(0, 0, 100, 100),
+                                      IntRect(0, 0, 100, 100));
+
+      // Check that the generated image is correct.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Red()));
+    }
+
+    {
+      ResetForNextPass(aSink);
+
+      // Check that the generated image is still the first pass image.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Red()));
+    }
+
+    {
+      // Fill the image with a second pass of green.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() {
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::FINISHED, result);
+      EXPECT_EQ(100u * 100u, count);
+
+      AssertCorrectPipelineFinalState(aSink,
+                                      IntRect(0, 0, 100, 100),
+                                      IntRect(0, 0, 100, 100));
+
+      // Check that the generated image is correct.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Green()));
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkInvalidRect)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    {
+      // Write one row.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 100) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        count++;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(100u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Assert that we have the right invalid rect.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, 0, 100, 1), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, 0, 100, 1), invalidRect->mOutputSpaceRect);
+    }
+
+    {
+      // Write eight rows.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 100 * 8) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        count++;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(100u * 8u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Assert that we have the right invalid rect.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, 1, 100, 8), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, 1, 100, 8), invalidRect->mOutputSpaceRect);
+    }
+
+    {
+      // Write the left half of one row.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 50) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        count++;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Assert that we don't have an invalid rect, since the invalid rect only
+      // gets updated when a row gets completed.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isNothing());
+    }
+
+    {
+      // Write the right half of the same row.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 50) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        count++;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Assert that we have the right invalid rect, which will include both the
+      // left and right halves of this row now that we've completed it.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, 9, 100, 1), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, 9, 100, 1), invalidRect->mOutputSpaceRect);
+    }
+
+    {
+      // Write no rows.
+      auto result = aSink->WritePixels<uint32_t>([&]() {
+        return AsVariant(WriteState::NEED_MORE_DATA);
+      });
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Assert that we don't have an invalid rect.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isNothing());
+    }
+
+    {
+      // Fill the rest of the image.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() {
+        count++;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::FINISHED, result);
+      EXPECT_EQ(100u * 90u, count);
+      EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+      // Assert that we have the right invalid rect.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, 10, 100, 90), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, 10, 100, 90), invalidRect->mOutputSpaceRect);
+
+      // Check that the generated image is correct.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Green()));
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkFlipVertically)
+{
+  WithSurfaceSink<Orient::FLIP_VERTICALLY>([](Decoder* aDecoder,
+                                              SurfaceSink* aSink) {
+    {
+      // Fill the image with a first pass of red.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() {
+        ++count;
+        return AsVariant(BGRAColor::Red().AsPixel());
+      });
+      EXPECT_EQ(WriteState::FINISHED, result);
+      EXPECT_EQ(100u * 100u, count);
+
+      AssertCorrectPipelineFinalState(aSink,
+                                      IntRect(0, 0, 100, 100),
+                                      IntRect(0, 0, 100, 100));
+
+      // Check that the generated image is correct.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Red()));
+    }
+
+    {
+      ResetForNextPass(aSink);
+
+      // Check that the generated image is still the first pass image.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Red()));
+    }
+
+    {
+      // Fill 25 rows of the image with green and make sure everything is OK.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+        if (count == 25 * 100) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        count++;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(25u * 100u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Assert that we have the right invalid rect, which should include the
+      // *bottom* (since we're flipping vertically) 25 rows of the image.
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, 75, 100, 25), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, 75, 100, 25), invalidRect->mOutputSpaceRect);
+
+      // Check that the generated image is correct.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(RowsAreSolidColor(surface, 0, 75, BGRAColor::Red()));
+      EXPECT_TRUE(RowsAreSolidColor(surface, 75, 25, BGRAColor::Green()));
+    }
+
+    {
+      // Fill the rest of the image with a second pass of green.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint32_t>([&]() {
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+      EXPECT_EQ(WriteState::FINISHED, result);
+      EXPECT_EQ(75u * 100u, count);
+
+      AssertCorrectPipelineFinalState(aSink,
+                                      IntRect(0, 0, 100, 75),
+                                      IntRect(0, 0, 100, 75));
+
+      // Check that the generated image is correct.
+      RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+      RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();
+      EXPECT_TRUE(IsSolidColor(surface, BGRAColor::Green()));
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkInitialization)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Check initial state.
+    EXPECT_FALSE(aSink->IsSurfaceFinished());
+    Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+    EXPECT_TRUE(invalidRect.isNothing());
+
+    // Check that the paletted image data is zero-initialized.
+    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
+    uint8_t* imageData = nullptr;
+    uint32_t imageLength = 0;
+    currentFrame->GetImageData(&imageData, &imageLength);
+    ASSERT_TRUE(imageData != nullptr);
+    ASSERT_EQ(100u * 100u, imageLength);
+    for (uint32_t i = 0; i < imageLength; ++i) {
+      ASSERT_EQ(uint8_t(0), imageData[i]);
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsFor0_0_100_100)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    CheckPalettedWritePixels(aDecoder, aSink);
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsFor25_25_50_50)
+{
+  WithPalettedSurfaceSink(IntRect(25, 25, 50, 50),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    CheckPalettedWritePixels(aDecoder, aSink,
+                             /* aOutputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputWriteRect = */ Some(IntRect(25, 25, 50, 50)),
+                             /* aOutputWriteRect = */ Some(IntRect(25, 25, 50, 50)));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsForMinus25_Minus25_50_50)
+{
+  WithPalettedSurfaceSink(IntRect(-25, -25, 50, 50),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    CheckPalettedWritePixels(aDecoder, aSink,
+                             /* aOutputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputWriteRect = */ Some(IntRect(-25, -25, 50, 50)),
+                             /* aOutputWriteRect = */ Some(IntRect(-25, -25, 50, 50)));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsFor75_Minus25_50_50)
+{
+  WithPalettedSurfaceSink(IntRect(75, -25, 50, 50),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    CheckPalettedWritePixels(aDecoder, aSink,
+                             /* aOutputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputWriteRect = */ Some(IntRect(75, -25, 50, 50)),
+                             /* aOutputWriteRect = */ Some(IntRect(75, -25, 50, 50)));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsForMinus25_75_50_50)
+{
+  WithPalettedSurfaceSink(IntRect(-25, 75, 50, 50),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    CheckPalettedWritePixels(aDecoder, aSink,
+                             /* aOutputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputWriteRect = */ Some(IntRect(-25, 75, 50, 50)),
+                             /* aOutputWriteRect = */ Some(IntRect(-25, 75, 50, 50)));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsFor75_75_50_50)
+{
+  WithPalettedSurfaceSink(IntRect(75, 75, 50, 50),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    CheckPalettedWritePixels(aDecoder, aSink,
+                             /* aOutputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputRect = */ Some(IntRect(0, 0, 50, 50)),
+                             /* aInputWriteRect = */ Some(IntRect(75, 75, 50, 50)),
+                             /* aOutputWriteRect = */ Some(IntRect(75, 75, 50, 50)));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsFinish)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Write nothing into the surface; just finish immediately.
+    uint32_t count = 0;
+    auto result = aSink->WritePixels<uint8_t>([&]{
+      count++;
+      return AsVariant(WriteState::FINISHED);
+    });
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(1u, count);
+
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixels<uint8_t>([&]() {
+      count++;
+      return AsVariant(uint8_t(128));
+    });
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is correct.
+    EXPECT_TRUE(IsSolidPalettedColor(aDecoder, 0));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsEarlyExit)
+{
+  auto checkEarlyExit =
+    [](Decoder* aDecoder, PalettedSurfaceSink* aSink, WriteState aState) {
+    // Write half a row of green pixels and then exit early with |aState|. If
+    // the lambda keeps getting called, we'll write red pixels, which will cause
+    // the test to fail.
+    uint32_t count = 0;
+    auto result = aSink->WritePixels<uint8_t>([&]() -> NextPixel<uint8_t> {
+      if (count == 50) {
+        return AsVariant(aState);
+      }
+      return count++ < 50 ? AsVariant(uint8_t(255)) : AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(aState, result);
+    EXPECT_EQ(50u, count);
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 50, 1));
+
+    if (aState != WriteState::FINISHED) {
+      // We should still be able to write more at this point.
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Verify that we can resume writing. We'll finish up the same row.
+      count = 0;
+      result = aSink->WritePixels<uint8_t>([&]() -> NextPixel<uint8_t> {
+        if (count == 50) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        ++count;
+        return AsVariant(uint8_t(255));
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+      CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 1));
+
+      return;
+    }
+
+    // We should've finished the surface at this point.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixels<uint8_t>([&]{
+      count++;
+      return AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 50, 1));
+  };
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::NEED_MORE_DATA);
+  });
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FAILURE);
+  });
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FINISHED);
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsToRow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Write the first 99 rows of our 100x100 surface and verify that even
+    // though our lambda will yield pixels forever, only one row is written per
+    // call to WritePixelsToRow().
+    for (int row = 0; row < 99; ++row) {
+      uint32_t count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint8_t>([&]{
+        ++count;
+        return AsVariant(uint8_t(255));
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(100u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mOutputSpaceRect);
+
+      CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, row + 1));
+    }
+
+    // Write the final line, which should finish the surface.
+    uint32_t count = 0;
+    WriteState result = aSink->WritePixelsToRow<uint8_t>([&]{
+      ++count;
+      return AsVariant(uint8_t(255));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(100u, count);
+
+    // Note that the final invalid rect we expect here is only the last row;
+    // that's because we called TakeInvalidRect() repeatedly in the loop above.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 99, 100, 1),
+                                    IntRect(0, 99, 100, 1));
+
+    // Check that the generated image is correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint8_t>([&]{
+      count++;
+      return AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 100));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsToRowEarlyExit)
+{
+  auto checkEarlyExit =
+    [](Decoder* aDecoder, PalettedSurfaceSink* aSink, WriteState aState) {
+    // Write half a row of 255s and then exit early with |aState|. If the lambda
+    // keeps getting called, we'll write 128s, which will cause the test to
+    // fail.
+    uint32_t count = 0;
+    auto result = aSink->WritePixelsToRow<uint8_t>([&]() -> NextPixel<uint8_t> {
+      if (count == 50) {
+        return AsVariant(aState);
+      }
+      return count++ < 50 ? AsVariant(uint8_t(255))
+                          : AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(aState, result);
+    EXPECT_EQ(50u, count);
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 50, 1));
+
+    if (aState != WriteState::FINISHED) {
+      // We should still be able to write more at this point.
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Verify that we can resume the same row and still stop at the end.
+      count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint8_t>([&]{
+        ++count;
+        return AsVariant(uint8_t(255));
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+      CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 1));
+
+      return;
+    }
+
+    // We should've finished the surface at this point.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint8_t>([&]{
+      count++;
+      return AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 50, 1));
+  };
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::NEED_MORE_DATA);
+  });
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FAILURE);
+  });
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                  [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FINISHED);
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteBuffer)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Create a buffer the same size as one row of the surface (which is 100x100),
+    // containing 60 pixels of 255 in the middle and 20 transparent pixels of 0 on
+    // either side.
+    uint8_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = 20 <= i && i < 80 ? 255 : 0;
+    }
+
+    // Write the buffer to every row of the surface and check that the generated
+    // image is correct.
+    CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(20, 0, 60, 100), [&]{
+      return aSink->WriteBuffer(buffer);
+    });
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteBufferPartialRow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Create a buffer the same size as one row of the surface, containing all
+    // 255 pixels.
+    uint8_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = 255;
+    }
+
+    // Write the buffer to the middle 60 pixels of every row of the surface and
+    // check that the generated image is correct.
+    CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(20, 0, 60, 100), [&]{
+      return aSink->WriteBuffer(buffer, 20, 60);
+    });
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteBufferPartialRowStartColOverflow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Create a buffer the same size as one row of the surface, containing all
+    // 255 pixels.
+    uint8_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = 255;
+    }
+
+    {
+      // Write the buffer to successive rows until every row of the surface
+      // has been written. We place the start column beyond the end of the row,
+      // which will prevent us from writing anything, so we check that the
+      // generated image is entirely 0.
+      CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(0, 0, 0, 0), [&]{
+        return aSink->WriteBuffer(buffer, 100, 100);
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Write the buffer to successive rows until every row of the surface
+      // has been written. We use column 50 as the start column, but we still
+      // write the buffer, which means we overflow the right edge of the surface
+      // by 50 pixels. We check that the left half of the generated image is
+      // 0 and the right half is 255.
+      CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(50, 0, 50, 100), [&]{
+        return aSink->WriteBuffer(buffer, 50, 100);
+      });
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteBufferPartialRowBufferOverflow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Create a buffer twice as large as a row of the surface. The first half
+    // (which is as large as a row of the image) will contain 255 pixels,
+    // while the second half will contain 128 pixels.
+    uint8_t buffer[200];
+    for (int i = 0; i < 200; ++i) {
+      buffer[i] = i < 100 ? 255 : 128;
+    }
+
+    {
+      // Write the buffer to successive rows until every row of the surface has
+      // been written. The buffer extends 100 pixels to the right of a row of
+      // the surface, but bounds checking will prevent us from overflowing the
+      // buffer. We check that the generated image is entirely 255 since the
+      // pixels on the right side of the buffer shouldn't have been written to
+      // the surface.
+      CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(0, 0, 100, 100), [&]{
+        return aSink->WriteBuffer(buffer, 0, 200);
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Write from the buffer to the middle of each row of the surface. That
+      // means that the left side of each row should be 0, since we didn't write
+      // anything there. A buffer overflow would cause us to write buffer
+      // contents into the left side of each row. We check that the generated
+      // image is 0 on the left side and 255 on the right.
+      CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(50, 0, 50, 100), [&]{
+        return aSink->WriteBuffer(buffer, 50, 200);
+      });
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteBufferFromNullSource)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Calling WriteBuffer() with a null pointer should fail without making any
+    // changes to the surface.
+    uint8_t* nullBuffer = nullptr;
+    WriteState result = aSink->WriteBuffer(nullBuffer);
+
+    EXPECT_EQ(WriteState::FAILURE, result);
+    EXPECT_FALSE(aSink->IsSurfaceFinished());
+    Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+    EXPECT_TRUE(invalidRect.isNothing());
+
+    // Check that nothing got written to the surface.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 0, 0));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteEmptyRow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    {
+      // Write an empty row to each row of the surface. We check that the
+      // generated image is entirely 0.
+      CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(0, 0, 0, 0), [&]{
+        return aSink->WriteEmptyRow();
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Write a partial row before we begin calling WriteEmptyRow(). We check
+      // that the generated image is entirely 0, which is to be expected since
+      // WriteEmptyRow() overwrites the current row even if some data has
+      // already been written to it.
+      uint32_t count = 0;
+      auto result = aSink->WritePixels<uint8_t>([&]() -> NextPixel<uint8_t> {
+        if (count == 50) {
+          return AsVariant(WriteState::NEED_MORE_DATA);
+        }
+        ++count;
+        return AsVariant(uint8_t(255));
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(0, 0, 0, 0), [&]{
+        return aSink->WriteEmptyRow();
+      });
+    }
+
+    ResetForNextPass(aSink);
+
+    {
+      // Create a buffer the same size as one row of the surface, containing all
+      // 255 pixels.
+      uint8_t buffer[100];
+      for (int i = 0; i < 100; ++i) {
+        buffer[i] = 255;
+      }
+
+      // Write an empty row to the middle 60 rows of the surface. The first 20
+      // and last 20 rows will be 255. (We need to use DoCheckIterativeWrite()
+      // here because we need a custom function to check the output, since it
+      // can't be described by a simple rect.)
+      auto writeFunc = [&](uint32_t aRow) {
+        if (aRow < 20 || aRow >= 80) {
+          return aSink->WriteBuffer(buffer);
+        } else {
+          return aSink->WriteEmptyRow();
+        }
+      };
+
+      auto checkFunc = [&]{
+        EXPECT_TRUE(PalettedRowsAreSolidColor(aDecoder, 0, 20, 255));
+        EXPECT_TRUE(PalettedRowsAreSolidColor(aDecoder, 20, 60, 0));
+        EXPECT_TRUE(PalettedRowsAreSolidColor(aDecoder, 80, 20, 255));
+      };
+
+      DoCheckIterativeWrite(aSink, writeFunc, checkFunc);
+    }
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteUnsafeComputedRow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Create an all-255 buffer the same size as one row of the surface.
+    uint8_t buffer[100];
+    for (int i = 0; i < 100; ++i) {
+      buffer[i] = 255;
+    }
+
+    // Write the buffer to successive rows until every row of the surface has
+    // been written. We only write to the right half of each row, so we check
+    // that the left side of the generated image is 0 and the right side is 255.
+    CheckPalettedIterativeWrite(aDecoder, aSink, IntRect(50, 0, 50, 100), [&]{
+      return aSink->WriteUnsafeComputedRow<uint8_t>([&](uint8_t* aRow,
+                                                        uint32_t aLength) {
+        EXPECT_EQ(100u, aLength );
+        memcpy(aRow + 50, buffer, 50 * sizeof(uint8_t));
+      });
+    });
+  });
+}