Add m-esr52 at 52.6.0

1 files changed, 1088 insertions, 0 deletions

diff --git a/gfx/thebes/gfxBlur.cpp b/gfx/thebes/gfxBlur.cpp
new file mode 100644
index 000000000..d5878e161
--- /dev/null
+++ b/gfx/thebes/gfxBlur.cpp
@@ -0,0 +1,1088 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * 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 "gfxBlur.h"
+
+#include "gfx2DGlue.h"
+#include "gfxContext.h"
+#include "gfxPlatform.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Blur.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "nsExpirationTracker.h"
+#include "nsClassHashtable.h"
+#include "gfxUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+gfxAlphaBoxBlur::gfxAlphaBoxBlur()
+{
+}
+
+gfxAlphaBoxBlur::~gfxAlphaBoxBlur()
+{
+  mContext = nullptr;
+}
+
+gfxContext*
+gfxAlphaBoxBlur::Init(const gfxRect& aRect,
+                      const IntSize& aSpreadRadius,
+                      const IntSize& aBlurRadius,
+                      const gfxRect* aDirtyRect,
+                      const gfxRect* aSkipRect)
+{
+    mozilla::gfx::Rect rect(Float(aRect.x), Float(aRect.y),
+                            Float(aRect.width), Float(aRect.height));
+    IntSize spreadRadius(aSpreadRadius.width, aSpreadRadius.height);
+    IntSize blurRadius(aBlurRadius.width, aBlurRadius.height);
+    UniquePtr<Rect> dirtyRect;
+    if (aDirtyRect) {
+      dirtyRect = MakeUnique<Rect>(Float(aDirtyRect->x),
+                                   Float(aDirtyRect->y),
+                                   Float(aDirtyRect->width),
+                                   Float(aDirtyRect->height));
+    }
+    UniquePtr<Rect> skipRect;
+    if (aSkipRect) {
+      skipRect = MakeUnique<Rect>(Float(aSkipRect->x),
+                                  Float(aSkipRect->y),
+                                  Float(aSkipRect->width),
+                                  Float(aSkipRect->height));
+    }
+
+    mBlur = MakeUnique<AlphaBoxBlur>(rect, spreadRadius, blurRadius, dirtyRect.get(), skipRect.get());
+    size_t blurDataSize = mBlur->GetSurfaceAllocationSize();
+    if (blurDataSize == 0)
+        return nullptr;
+
+    IntSize size = mBlur->GetSize();
+
+    // Make an alpha-only surface to draw on. We will play with the data after
+    // everything is drawn to create a blur effect.
+    mData = MakeUniqueFallible<unsigned char[]>(blurDataSize);
+    if (!mData) {
+        return nullptr;
+    }
+    memset(mData.get(), 0, blurDataSize);
+
+    RefPtr<DrawTarget> dt =
+        gfxPlatform::CreateDrawTargetForData(mData.get(), size,
+                                             mBlur->GetStride(),
+                                             SurfaceFormat::A8);
+    if (!dt || !dt->IsValid()) {
+        return nullptr;
+    }
+
+    IntRect irect = mBlur->GetRect();
+    gfxPoint topleft(irect.TopLeft().x, irect.TopLeft().y);
+
+    mContext = gfxContext::CreateOrNull(dt);
+    MOZ_ASSERT(mContext); // already checked for target above
+    mContext->SetMatrix(gfxMatrix::Translation(-topleft));
+
+    return mContext;
+}
+
+void
+DrawBlur(gfxContext* aDestinationCtx,
+         SourceSurface* aBlur,
+         const IntPoint& aTopLeft,
+         const Rect* aDirtyRect)
+{
+    DrawTarget *dest = aDestinationCtx->GetDrawTarget();
+
+    RefPtr<gfxPattern> thebesPat = aDestinationCtx->GetPattern();
+    Pattern* pat = thebesPat->GetPattern(dest, nullptr);
+
+    Matrix oldTransform = dest->GetTransform();
+    Matrix newTransform = oldTransform;
+    newTransform.PreTranslate(aTopLeft.x, aTopLeft.y);
+
+    // Avoid a semi-expensive clip operation if we can, otherwise
+    // clip to the dirty rect
+    if (aDirtyRect) {
+        dest->PushClipRect(*aDirtyRect);
+    }
+
+    dest->SetTransform(newTransform);
+    dest->MaskSurface(*pat, aBlur, Point(0, 0));
+    dest->SetTransform(oldTransform);
+
+    if (aDirtyRect) {
+        dest->PopClip();
+    }
+}
+
+already_AddRefed<SourceSurface>
+gfxAlphaBoxBlur::DoBlur(DrawTarget* aDT, IntPoint* aTopLeft)
+{
+    mBlur->Blur(mData.get());
+
+    *aTopLeft = mBlur->GetRect().TopLeft();
+
+    return aDT->CreateSourceSurfaceFromData(mData.get(),
+                                            mBlur->GetSize(),
+                                            mBlur->GetStride(),
+                                            SurfaceFormat::A8);
+}
+
+void
+gfxAlphaBoxBlur::Paint(gfxContext* aDestinationCtx)
+{
+    if (!mContext)
+        return;
+
+    DrawTarget *dest = aDestinationCtx->GetDrawTarget();
+    if (!dest) {
+      NS_WARNING("Blurring not supported for Thebes contexts!");
+      return;
+    }
+
+    Rect* dirtyRect = mBlur->GetDirtyRect();
+
+    IntPoint topLeft;
+    RefPtr<SourceSurface> mask = DoBlur(dest, &topLeft);
+    if (!mask) {
+      NS_ERROR("Failed to create mask!");
+      return;
+    }
+
+    DrawBlur(aDestinationCtx, mask, topLeft, dirtyRect);
+}
+
+IntSize gfxAlphaBoxBlur::CalculateBlurRadius(const gfxPoint& aStd)
+{
+    mozilla::gfx::Point std(Float(aStd.x), Float(aStd.y));
+    IntSize size = AlphaBoxBlur::CalculateBlurRadius(std);
+    return IntSize(size.width, size.height);
+}
+
+struct BlurCacheKey : public PLDHashEntryHdr {
+  typedef const BlurCacheKey& KeyType;
+  typedef const BlurCacheKey* KeyTypePointer;
+  enum { ALLOW_MEMMOVE = true };
+
+  IntSize mMinSize;
+  IntSize mBlurRadius;
+  Color mShadowColor;
+  BackendType mBackend;
+  RectCornerRadii mCornerRadii;
+  bool mIsInset;
+
+  // Only used for inset blurs
+  bool mHasBorderRadius;
+  IntSize mInnerMinSize;
+
+  BlurCacheKey(IntSize aMinSize, IntSize aBlurRadius,
+               RectCornerRadii* aCornerRadii, const Color& aShadowColor,
+               BackendType aBackendType)
+    : BlurCacheKey(aMinSize, IntSize(0, 0),
+                   aBlurRadius, aCornerRadii,
+                   aShadowColor, false,
+                   false, aBackendType)
+  {}
+
+  explicit BlurCacheKey(const BlurCacheKey* aOther)
+    : mMinSize(aOther->mMinSize)
+    , mBlurRadius(aOther->mBlurRadius)
+    , mShadowColor(aOther->mShadowColor)
+    , mBackend(aOther->mBackend)
+    , mCornerRadii(aOther->mCornerRadii)
+    , mIsInset(aOther->mIsInset)
+    , mHasBorderRadius(aOther->mHasBorderRadius)
+    , mInnerMinSize(aOther->mInnerMinSize)
+  { }
+
+  explicit BlurCacheKey(IntSize aOuterMinSize, IntSize aInnerMinSize,
+                        IntSize aBlurRadius,
+                        const RectCornerRadii* aCornerRadii,
+                        const Color& aShadowColor, bool aIsInset,
+                        bool aHasBorderRadius, BackendType aBackendType)
+    : mMinSize(aOuterMinSize)
+    , mBlurRadius(aBlurRadius)
+    , mShadowColor(aShadowColor)
+    , mBackend(aBackendType)
+    , mCornerRadii(aCornerRadii ? *aCornerRadii : RectCornerRadii())
+    , mIsInset(aIsInset)
+    , mHasBorderRadius(aHasBorderRadius)
+    , mInnerMinSize(aInnerMinSize)
+  { }
+
+  static PLDHashNumber
+  HashKey(const KeyTypePointer aKey)
+  {
+    PLDHashNumber hash = 0;
+    hash = AddToHash(hash, aKey->mMinSize.width, aKey->mMinSize.height);
+    hash = AddToHash(hash, aKey->mBlurRadius.width, aKey->mBlurRadius.height);
+
+    hash = AddToHash(hash, HashBytes(&aKey->mShadowColor.r,
+                                     sizeof(aKey->mShadowColor.r)));
+    hash = AddToHash(hash, HashBytes(&aKey->mShadowColor.g,
+                                     sizeof(aKey->mShadowColor.g)));
+    hash = AddToHash(hash, HashBytes(&aKey->mShadowColor.b,
+                                     sizeof(aKey->mShadowColor.b)));
+    hash = AddToHash(hash, HashBytes(&aKey->mShadowColor.a,
+                                     sizeof(aKey->mShadowColor.a)));
+
+    for (int i = 0; i < 4; i++) {
+      hash = AddToHash(hash, aKey->mCornerRadii[i].width, aKey->mCornerRadii[i].height);
+    }
+
+    hash = AddToHash(hash, (uint32_t)aKey->mBackend);
+
+    if (aKey->mIsInset) {
+      hash = AddToHash(hash, aKey->mInnerMinSize.width, aKey->mInnerMinSize.height);
+      hash = AddToHash(hash, HashBytes(&aKey->mHasBorderRadius, sizeof(bool)));
+    }
+    return hash;
+  }
+
+  bool
+  KeyEquals(KeyTypePointer aKey) const
+  {
+    if (aKey->mMinSize == mMinSize &&
+        aKey->mBlurRadius == mBlurRadius &&
+        aKey->mCornerRadii == mCornerRadii &&
+        aKey->mShadowColor == mShadowColor &&
+        aKey->mBackend == mBackend) {
+
+      if (mIsInset) {
+        return (mHasBorderRadius == aKey->mHasBorderRadius) &&
+                (mInnerMinSize == aKey->mInnerMinSize);
+      }
+
+      return true;
+     }
+
+     return false;
+  }
+
+  static KeyTypePointer
+  KeyToPointer(KeyType aKey)
+  {
+    return &aKey;
+  }
+};
+
+/**
+ * This class is what is cached. It need to be allocated in an object separated
+ * to the cache entry to be able to be tracked by the nsExpirationTracker.
+ * */
+struct BlurCacheData {
+  BlurCacheData(SourceSurface* aBlur, IntMargin aExtendDestBy, const BlurCacheKey& aKey)
+    : mBlur(aBlur)
+    , mExtendDest(aExtendDestBy)
+    , mKey(aKey)
+  {}
+
+  BlurCacheData(const BlurCacheData& aOther)
+    : mBlur(aOther.mBlur)
+    , mExtendDest(aOther.mExtendDest)
+    , mKey(aOther.mKey)
+  { }
+
+  nsExpirationState *GetExpirationState() {
+    return &mExpirationState;
+  }
+
+  nsExpirationState mExpirationState;
+  RefPtr<SourceSurface> mBlur;
+  IntMargin mExtendDest;
+  BlurCacheKey mKey;
+};
+
+/**
+ * This class implements a cache with no maximum size, that retains the
+ * SourceSurfaces used to draw the blurs.
+ *
+ * An entry stays in the cache as long as it is used often.
+ */
+class BlurCache final : public nsExpirationTracker<BlurCacheData,4>
+{
+  public:
+    BlurCache()
+      : nsExpirationTracker<BlurCacheData, 4>(GENERATION_MS, "BlurCache")
+    {
+    }
+
+    virtual void NotifyExpired(BlurCacheData* aObject)
+    {
+      RemoveObject(aObject);
+      mHashEntries.Remove(aObject->mKey);
+    }
+
+    BlurCacheData* Lookup(const IntSize aMinSize,
+                          const IntSize& aBlurRadius,
+                          RectCornerRadii* aCornerRadii,
+                          const Color& aShadowColor,
+                          BackendType aBackendType)
+    {
+      BlurCacheData* blur =
+        mHashEntries.Get(BlurCacheKey(aMinSize, aBlurRadius,
+                                      aCornerRadii, aShadowColor,
+                                      aBackendType));
+      if (blur) {
+        MarkUsed(blur);
+      }
+
+      return blur;
+    }
+
+    BlurCacheData* LookupInsetBoxShadow(const IntSize aOuterMinSize,
+                                        const IntSize aInnerMinSize,
+                                        const IntSize& aBlurRadius,
+                                        const RectCornerRadii* aCornerRadii,
+                                        const Color& aShadowColor,
+                                        const bool& aHasBorderRadius,
+                                        BackendType aBackendType)
+    {
+      bool insetBoxShadow = true;
+      BlurCacheKey key(aOuterMinSize, aInnerMinSize,
+                       aBlurRadius, aCornerRadii,
+                       aShadowColor, insetBoxShadow,
+                       aHasBorderRadius, aBackendType);
+      BlurCacheData* blur = mHashEntries.Get(key);
+      if (blur) {
+        MarkUsed(blur);
+      }
+
+      return blur;
+    }
+
+    // Returns true if we successfully register the blur in the cache, false
+    // otherwise.
+    bool RegisterEntry(BlurCacheData* aValue)
+    {
+      nsresult rv = AddObject(aValue);
+      if (NS_FAILED(rv)) {
+        // We are OOM, and we cannot track this object. We don't want stall
+        // entries in the hash table (since the expiration tracker is responsible
+        // for removing the cache entries), so we avoid putting that entry in the
+        // table, which is a good things considering we are short on memory
+        // anyway, we probably don't want to retain things.
+        return false;
+      }
+      mHashEntries.Put(aValue->mKey, aValue);
+      return true;
+    }
+
+  protected:
+    static const uint32_t GENERATION_MS = 1000;
+    /**
+     * FIXME use nsTHashtable to avoid duplicating the BlurCacheKey.
+     * https://bugzilla.mozilla.org/show_bug.cgi?id=761393#c47
+     */
+    nsClassHashtable<BlurCacheKey, BlurCacheData> mHashEntries;
+};
+
+static BlurCache* gBlurCache = nullptr;
+
+static IntSize
+ComputeMinSizeForShadowShape(RectCornerRadii* aCornerRadii,
+                             IntSize aBlurRadius,
+                             IntMargin& aSlice,
+                             const IntSize& aRectSize)
+{
+  float cornerWidth = 0;
+  float cornerHeight = 0;
+  if (aCornerRadii) {
+    RectCornerRadii corners = *aCornerRadii;
+    for (size_t i = 0; i < 4; i++) {
+      cornerWidth = std::max(cornerWidth, corners[i].width);
+      cornerHeight = std::max(cornerHeight, corners[i].height);
+    }
+  }
+
+  aSlice = IntMargin(ceil(cornerHeight) + aBlurRadius.height,
+                     ceil(cornerWidth) + aBlurRadius.width,
+                     ceil(cornerHeight) + aBlurRadius.height,
+                     ceil(cornerWidth) + aBlurRadius.width);
+
+  IntSize minSize(aSlice.LeftRight() + 1,
+                      aSlice.TopBottom() + 1);
+
+  // If aRectSize is smaller than minSize, the border-image approach won't
+  // work; there's no way to squeeze parts of the min box-shadow source
+  // image such that the result looks correct. So we need to adjust minSize
+  // in such a way that we can later draw it without stretching in the affected
+  // dimension. We also need to adjust "slice" to ensure that we're not trying
+  // to slice away more than we have.
+  if (aRectSize.width < minSize.width) {
+    minSize.width = aRectSize.width;
+    aSlice.left = 0;
+    aSlice.right = 0;
+  }
+  if (aRectSize.height < minSize.height) {
+    minSize.height = aRectSize.height;
+    aSlice.top = 0;
+    aSlice.bottom = 0;
+  }
+
+  MOZ_ASSERT(aSlice.LeftRight() <= minSize.width);
+  MOZ_ASSERT(aSlice.TopBottom() <= minSize.height);
+  return minSize;
+}
+
+void
+CacheBlur(DrawTarget& aDT,
+          const IntSize& aMinSize,
+          const IntSize& aBlurRadius,
+          RectCornerRadii* aCornerRadii,
+          const Color& aShadowColor,
+          IntMargin aExtendDest,
+          SourceSurface* aBoxShadow)
+{
+  BlurCacheKey key(aMinSize, aBlurRadius, aCornerRadii, aShadowColor, aDT.GetBackendType());
+  BlurCacheData* data = new BlurCacheData(aBoxShadow, aExtendDest, key);
+  if (!gBlurCache->RegisterEntry(data)) {
+    delete data;
+  }
+}
+
+// Blurs a small surface and creates the mask.
+static already_AddRefed<SourceSurface>
+CreateBlurMask(const IntSize& aMinSize,
+               RectCornerRadii* aCornerRadii,
+               IntSize aBlurRadius,
+               IntMargin& aExtendDestBy,
+               IntMargin& aSliceBorder,
+               DrawTarget& aDestDrawTarget)
+{
+  gfxAlphaBoxBlur blur;
+  IntRect minRect(IntPoint(), aMinSize);
+
+  gfxContext* blurCtx = blur.Init(ThebesRect(Rect(minRect)), IntSize(),
+                                  aBlurRadius, nullptr, nullptr);
+
+  if (!blurCtx) {
+    return nullptr;
+  }
+
+  DrawTarget* blurDT = blurCtx->GetDrawTarget();
+  ColorPattern black(Color(0.f, 0.f, 0.f, 1.f));
+
+  if (aCornerRadii) {
+    RefPtr<Path> roundedRect =
+      MakePathForRoundedRect(*blurDT, Rect(minRect), *aCornerRadii);
+    blurDT->Fill(roundedRect, black);
+  } else {
+    blurDT->FillRect(Rect(minRect), black);
+  }
+
+  IntPoint topLeft;
+  RefPtr<SourceSurface> result = blur.DoBlur(&aDestDrawTarget, &topLeft);
+  if (!result) {
+    return nullptr;
+  }
+
+  IntRect expandedMinRect(topLeft, result->GetSize());
+  aExtendDestBy = expandedMinRect - minRect;
+  aSliceBorder += aExtendDestBy;
+
+  MOZ_ASSERT(aSliceBorder.LeftRight() <= expandedMinRect.width);
+  MOZ_ASSERT(aSliceBorder.TopBottom() <= expandedMinRect.height);
+
+  return result.forget();
+}
+
+static already_AddRefed<SourceSurface>
+CreateBoxShadow(DrawTarget& aDestDT, SourceSurface* aBlurMask, const Color& aShadowColor)
+{
+  IntSize blurredSize = aBlurMask->GetSize();
+  RefPtr<DrawTarget> boxShadowDT =
+    Factory::CreateDrawTarget(aDestDT.GetBackendType(), blurredSize, SurfaceFormat::B8G8R8A8);
+
+  if (!boxShadowDT) {
+    return nullptr;
+  }
+
+  ColorPattern shadowColor(ToDeviceColor(aShadowColor));
+  boxShadowDT->MaskSurface(shadowColor, aBlurMask, Point(0, 0));
+  return boxShadowDT->Snapshot();
+}
+
+static already_AddRefed<SourceSurface>
+GetBlur(gfxContext* aDestinationCtx,
+        const IntSize& aRectSize,
+        const IntSize& aBlurRadius,
+        RectCornerRadii* aCornerRadii,
+        const Color& aShadowColor,
+        IntMargin& aExtendDestBy,
+        IntMargin& aSlice)
+{
+  if (!gBlurCache) {
+    gBlurCache = new BlurCache();
+  }
+
+  IntSize minSize =
+    ComputeMinSizeForShadowShape(aCornerRadii, aBlurRadius, aSlice, aRectSize);
+
+  // We can get seams using the min size rect when drawing to the destination rect
+  // if we have a non-pixel aligned destination transformation. In those cases,
+  // fallback to just rendering the destination rect.
+  Matrix destMatrix = ToMatrix(aDestinationCtx->CurrentMatrix());
+  bool useDestRect = !destMatrix.IsRectilinear() || destMatrix.HasNonIntegerTranslation();
+  if (useDestRect) {
+    minSize = aRectSize;
+  }
+
+  DrawTarget& destDT = *aDestinationCtx->GetDrawTarget();
+
+  BlurCacheData* cached = gBlurCache->Lookup(minSize, aBlurRadius,
+                                             aCornerRadii, aShadowColor,
+                                             destDT.GetBackendType());
+  if (cached && !useDestRect) {
+    // See CreateBlurMask() for these values
+    aExtendDestBy = cached->mExtendDest;
+    aSlice = aSlice + aExtendDestBy;
+    RefPtr<SourceSurface> blur = cached->mBlur;
+    return blur.forget();
+  }
+
+  RefPtr<SourceSurface> blurMask =
+    CreateBlurMask(minSize, aCornerRadii, aBlurRadius, aExtendDestBy, aSlice,
+                   destDT);
+
+  if (!blurMask) {
+    return nullptr;
+  }
+
+  RefPtr<SourceSurface> boxShadow = CreateBoxShadow(destDT, blurMask, aShadowColor);
+  if (!boxShadow) {
+    return nullptr;
+  }
+
+  if (useDestRect) {
+    // Since we're just going to paint the actual rect to the destination
+    aSlice.SizeTo(0, 0, 0, 0);
+  } else {
+    CacheBlur(destDT, minSize, aBlurRadius, aCornerRadii, aShadowColor,
+              aExtendDestBy, boxShadow);
+  }
+  return boxShadow.forget();
+}
+
+void
+gfxAlphaBoxBlur::ShutdownBlurCache()
+{
+  delete gBlurCache;
+  gBlurCache = nullptr;
+}
+
+static Rect
+RectWithEdgesTRBL(Float aTop, Float aRight, Float aBottom, Float aLeft)
+{
+  return Rect(aLeft, aTop, aRight - aLeft, aBottom - aTop);
+}
+
+static void
+RepeatOrStretchSurface(DrawTarget& aDT, SourceSurface* aSurface,
+                       const Rect& aDest, const Rect& aSrc, Rect& aSkipRect)
+{
+  if (aSkipRect.Contains(aDest)) {
+    return;
+  }
+
+  if ((!aDT.GetTransform().IsRectilinear() &&
+       aDT.GetBackendType() != BackendType::CAIRO) ||
+      (aDT.GetBackendType() == BackendType::DIRECT2D1_1)) {
+    // Use stretching if possible, since it leads to less seams when the
+    // destination is transformed. However, don't do this if we're using cairo,
+    // because if cairo is using pixman it won't render anything for large
+    // stretch factors because pixman's internal fixed point precision is not
+    // high enough to handle those scale factors.
+    // Calling FillRect on a D2D backend with a repeating pattern is much slower
+    // than DrawSurface, so special case the D2D backend here.
+    aDT.DrawSurface(aSurface, aDest, aSrc);
+    return;
+  }
+
+  SurfacePattern pattern(aSurface, ExtendMode::REPEAT,
+                         Matrix::Translation(aDest.TopLeft() - aSrc.TopLeft()),
+                         SamplingFilter::GOOD, RoundedToInt(aSrc));
+  aDT.FillRect(aDest, pattern);
+}
+
+static void
+DrawCorner(DrawTarget& aDT, SourceSurface* aSurface,
+           const Rect& aDest, const Rect& aSrc, Rect& aSkipRect)
+{
+  if (aSkipRect.Contains(aDest)) {
+    return;
+  }
+
+  aDT.DrawSurface(aSurface, aDest, aSrc);
+}
+
+static void
+DrawBoxShadows(DrawTarget& aDestDrawTarget, SourceSurface* aSourceBlur,
+               Rect aDstOuter, Rect aDstInner, Rect aSrcOuter, Rect aSrcInner,
+               Rect aSkipRect)
+{
+  // Corners: top left, top right, bottom left, bottom right
+  DrawCorner(aDestDrawTarget, aSourceBlur,
+             RectWithEdgesTRBL(aDstOuter.Y(), aDstInner.X(),
+                               aDstInner.Y(), aDstOuter.X()),
+             RectWithEdgesTRBL(aSrcOuter.Y(), aSrcInner.X(),
+                               aSrcInner.Y(), aSrcOuter.X()),
+                               aSkipRect);
+
+  DrawCorner(aDestDrawTarget, aSourceBlur,
+             RectWithEdgesTRBL(aDstOuter.Y(), aDstOuter.XMost(),
+                               aDstInner.Y(), aDstInner.XMost()),
+             RectWithEdgesTRBL(aSrcOuter.Y(), aSrcOuter.XMost(),
+                               aSrcInner.Y(), aSrcInner.XMost()),
+             aSkipRect);
+
+  DrawCorner(aDestDrawTarget, aSourceBlur,
+             RectWithEdgesTRBL(aDstInner.YMost(), aDstInner.X(),
+                               aDstOuter.YMost(), aDstOuter.X()),
+             RectWithEdgesTRBL(aSrcInner.YMost(), aSrcInner.X(),
+                               aSrcOuter.YMost(), aSrcOuter.X()),
+             aSkipRect);
+
+  DrawCorner(aDestDrawTarget, aSourceBlur,
+             RectWithEdgesTRBL(aDstInner.YMost(), aDstOuter.XMost(),
+                               aDstOuter.YMost(), aDstInner.XMost()),
+             RectWithEdgesTRBL(aSrcInner.YMost(), aSrcOuter.XMost(),
+                               aSrcOuter.YMost(), aSrcInner.XMost()),
+             aSkipRect);
+
+  // Edges: top, left, right, bottom
+  RepeatOrStretchSurface(aDestDrawTarget, aSourceBlur,
+                         RectWithEdgesTRBL(aDstOuter.Y(), aDstInner.XMost(),
+                                           aDstInner.Y(), aDstInner.X()),
+                         RectWithEdgesTRBL(aSrcOuter.Y(), aSrcInner.XMost(),
+                                           aSrcInner.Y(), aSrcInner.X()),
+                         aSkipRect);
+  RepeatOrStretchSurface(aDestDrawTarget, aSourceBlur,
+                         RectWithEdgesTRBL(aDstInner.Y(), aDstInner.X(),
+                                           aDstInner.YMost(), aDstOuter.X()),
+                         RectWithEdgesTRBL(aSrcInner.Y(), aSrcInner.X(),
+                                           aSrcInner.YMost(), aSrcOuter.X()),
+                         aSkipRect);
+
+  RepeatOrStretchSurface(aDestDrawTarget, aSourceBlur,
+                         RectWithEdgesTRBL(aDstInner.Y(), aDstOuter.XMost(),
+                                           aDstInner.YMost(), aDstInner.XMost()),
+                         RectWithEdgesTRBL(aSrcInner.Y(), aSrcOuter.XMost(),
+                                           aSrcInner.YMost(), aSrcInner.XMost()),
+                         aSkipRect);
+  RepeatOrStretchSurface(aDestDrawTarget, aSourceBlur,
+                         RectWithEdgesTRBL(aDstInner.YMost(), aDstInner.XMost(),
+                                           aDstOuter.YMost(), aDstInner.X()),
+                         RectWithEdgesTRBL(aSrcInner.YMost(), aSrcInner.XMost(),
+                                           aSrcOuter.YMost(), aSrcInner.X()),
+                         aSkipRect);
+}
+
+/***
+ * We draw a blurred a rectangle by only blurring a smaller rectangle and
+ * splitting the rectangle into 9 parts.
+ * First, a small minimum source rect is calculated and used to create a blur
+ * mask since the actual blurring itself is expensive. Next, we use the mask
+ * with the given shadow color to create a minimally-sized box shadow of the
+ * right color. Finally, we cut out the 9 parts from the box-shadow source and
+ * paint each part in the right place, stretching the non-corner parts to fill
+ * the space between the corners.
+ */
+
+/* static */ void
+gfxAlphaBoxBlur::BlurRectangle(gfxContext* aDestinationCtx,
+                               const gfxRect& aRect,
+                               RectCornerRadii* aCornerRadii,
+                               const gfxPoint& aBlurStdDev,
+                               const Color& aShadowColor,
+                               const gfxRect& aDirtyRect,
+                               const gfxRect& aSkipRect)
+{
+  IntSize blurRadius = CalculateBlurRadius(aBlurStdDev);
+
+  IntRect rect = RoundedToInt(ToRect(aRect));
+  IntMargin extendDestBy;
+  IntMargin slice;
+
+  RefPtr<SourceSurface> boxShadow = GetBlur(aDestinationCtx,
+                                            rect.Size(), blurRadius,
+                                            aCornerRadii, aShadowColor,
+                                            extendDestBy, slice);
+  if (!boxShadow) {
+    return;
+  }
+
+  DrawTarget& destDrawTarget = *aDestinationCtx->GetDrawTarget();
+  destDrawTarget.PushClipRect(ToRect(aDirtyRect));
+
+  // Copy the right parts from boxShadow into destDrawTarget. The middle parts
+  // will be stretched, border-image style.
+
+  Rect srcOuter(Point(), Size(boxShadow->GetSize()));
+  Rect srcInner = srcOuter;
+  srcInner.Deflate(Margin(slice));
+
+  rect.Inflate(extendDestBy);
+  Rect dstOuter(rect);
+  Rect dstInner(rect);
+  dstInner.Deflate(Margin(slice));
+
+  Rect skipRect = ToRect(aSkipRect);
+
+  if (srcInner.IsEqualInterior(srcOuter)) {
+    MOZ_ASSERT(dstInner.IsEqualInterior(dstOuter));
+    // The target rect is smaller than the minimal size so just draw the surface
+    destDrawTarget.DrawSurface(boxShadow, dstInner, srcInner);
+  } else {
+    DrawBoxShadows(destDrawTarget, boxShadow, dstOuter, dstInner,
+                   srcOuter, srcInner, skipRect);
+
+    // Middle part
+    RepeatOrStretchSurface(destDrawTarget, boxShadow,
+                           RectWithEdgesTRBL(dstInner.Y(), dstInner.XMost(),
+                                             dstInner.YMost(), dstInner.X()),
+                           RectWithEdgesTRBL(srcInner.Y(), srcInner.XMost(),
+                                             srcInner.YMost(), srcInner.X()),
+                           skipRect);
+  }
+
+  // A note about anti-aliasing and seems between adjacent parts:
+  // We don't explicitly disable anti-aliasing in the DrawSurface calls above,
+  // so if there's a transform on destDrawTarget that is not pixel-aligned,
+  // there will be seams between adjacent parts of the box-shadow. It's hard to
+  // avoid those without the use of an intermediate surface.
+  // You might think that we could avoid those by just turning of AA, but there
+  // is a problem with that: Box-shadow rendering needs to clip out the
+  // element's border box, and we'd like that clip to have anti-aliasing -
+  // especially if the element has rounded corners! So we can't do that unless
+  // we have a way to say "Please anti-alias the clip, but don't antialias the
+  // destination rect of the DrawSurface call".
+  // On OS X there is an additional problem with turning off AA: CoreGraphics
+  // will not just fill the pixels that have their pixel center inside the
+  // filled shape. Instead, it will fill all the pixels which are partially
+  // covered by the shape. So for pixels on the edge between two adjacent parts,
+  // all those pixels will be painted to by both parts, which looks very bad.
+
+  destDrawTarget.PopClip();
+}
+
+static already_AddRefed<Path>
+GetBoxShadowInsetPath(DrawTarget* aDrawTarget,
+                      const Rect aOuterRect, const Rect aInnerRect,
+                      const bool aHasBorderRadius, const RectCornerRadii& aInnerClipRadii)
+{
+  /***
+   * We create an inset path by having two rects.
+   *
+   *  -----------------------
+   *  |  ________________   |
+   *  | |                |  |
+   *  | |                |  |
+   *  | ------------------  |
+   *  |_____________________|
+   *
+   * The outer rect and the inside rect. The path
+   * creates a frame around the content where we draw the inset shadow.
+   */
+  RefPtr<PathBuilder> builder =
+    aDrawTarget->CreatePathBuilder(FillRule::FILL_EVEN_ODD);
+  AppendRectToPath(builder, aOuterRect, true);
+
+  if (aHasBorderRadius) {
+    AppendRoundedRectToPath(builder, aInnerRect, aInnerClipRadii, false);
+  } else {
+    AppendRectToPath(builder, aInnerRect, false);
+  }
+  return builder->Finish();
+}
+
+static void
+FillDestinationPath(gfxContext* aDestinationCtx,
+                    const Rect aDestinationRect,
+                    const Rect aShadowClipRect,
+                    const Color& aShadowColor,
+                    const bool aHasBorderRadius,
+                    const RectCornerRadii& aInnerClipRadii)
+{
+  // When there is no blur radius, fill the path onto the destination
+  // surface.
+  aDestinationCtx->SetColor(aShadowColor);
+  DrawTarget* destDrawTarget = aDestinationCtx->GetDrawTarget();
+  RefPtr<Path> shadowPath = GetBoxShadowInsetPath(destDrawTarget, aDestinationRect,
+                                                  aShadowClipRect, aHasBorderRadius,
+                                                  aInnerClipRadii);
+
+  aDestinationCtx->SetPath(shadowPath);
+  aDestinationCtx->Fill();
+}
+
+static void
+CacheInsetBlur(const IntSize aMinOuterSize,
+               const IntSize aMinInnerSize,
+               const IntSize& aBlurRadius,
+               const RectCornerRadii* aCornerRadii,
+               const Color& aShadowColor,
+               const bool& aHasBorderRadius,
+               BackendType aBackendType,
+               SourceSurface* aBoxShadow)
+{
+  bool isInsetBlur = true;
+  BlurCacheKey key(aMinOuterSize, aMinInnerSize,
+                   aBlurRadius, aCornerRadii,
+                   aShadowColor, isInsetBlur,
+                   aHasBorderRadius, aBackendType);
+  IntMargin extendDestBy(0, 0, 0, 0);
+  BlurCacheData* data = new BlurCacheData(aBoxShadow, extendDestBy, key);
+  if (!gBlurCache->RegisterEntry(data)) {
+    delete data;
+  }
+}
+
+already_AddRefed<mozilla::gfx::SourceSurface>
+gfxAlphaBoxBlur::GetInsetBlur(const mozilla::gfx::Rect aOuterRect,
+                              const mozilla::gfx::Rect aWhitespaceRect,
+                              const bool aIsDestRect,
+                              const mozilla::gfx::Color& aShadowColor,
+                              const mozilla::gfx::IntSize& aBlurRadius,
+                              const bool aHasBorderRadius,
+                              const RectCornerRadii& aInnerClipRadii,
+                              DrawTarget* aDestDrawTarget)
+{
+  if (!gBlurCache) {
+    gBlurCache = new BlurCache();
+  }
+
+  IntSize outerSize((int)aOuterRect.width, (int)aOuterRect.height);
+  IntSize whitespaceSize((int)aWhitespaceRect.width, (int)aWhitespaceRect.height);
+  BlurCacheData* cached =
+      gBlurCache->LookupInsetBoxShadow(outerSize, whitespaceSize,
+                                       aBlurRadius, &aInnerClipRadii,
+                                       aShadowColor, aHasBorderRadius,
+                                       aDestDrawTarget->GetBackendType());
+
+  if (cached && !aIsDestRect) {
+    // So we don't forget the actual cached blur
+    RefPtr<SourceSurface> cachedBlur = cached->mBlur;
+    return cachedBlur.forget();
+  }
+
+  // If we can do a min rect, the whitespace rect will be expanded in Init to
+  // aOuterRect.
+  Rect blurRect = aIsDestRect ? aOuterRect : aWhitespaceRect;
+  IntSize zeroSpread(0, 0);
+  gfxContext* minGfxContext = Init(ThebesRect(blurRect),
+                                   zeroSpread, aBlurRadius,
+                                   nullptr, nullptr);
+  if (!minGfxContext) {
+    return nullptr;
+  }
+
+  // This is really annoying. When we create the AlphaBoxBlur, the gfxContext
+  // has a translation applied to it that is the topLeft point. This is actually
+  // the rect we gave it plus the blur radius. The rects we give this for the outer
+  // and whitespace rects are based at (0, 0). We could either translate those rects
+  // when we don't have a destination rect or ignore the translation when using
+  // the dest rect. The dest rects layout gives us expect this translation.
+  if (!aIsDestRect) {
+    minGfxContext->SetMatrix(gfxMatrix());
+  }
+
+  DrawTarget* minDrawTarget = minGfxContext->GetDrawTarget();
+
+  // Fill in the path between the inside white space / outer rects
+  // NOT the inner frame
+  RefPtr<Path> maskPath =
+    GetBoxShadowInsetPath(minDrawTarget, aOuterRect,
+                          aWhitespaceRect, aHasBorderRadius,
+                          aInnerClipRadii);
+
+  Color black(0.f, 0.f, 0.f, 1.f);
+  minGfxContext->SetColor(black);
+  minGfxContext->SetPath(maskPath);
+  minGfxContext->Fill();
+
+  // Create the A8 mask
+  IntPoint topLeft;
+  RefPtr<SourceSurface> minMask = DoBlur(minDrawTarget, &topLeft);
+  if (!minMask) {
+    return nullptr;
+  }
+
+  // Fill in with the color we actually wanted
+  RefPtr<SourceSurface> minInsetBlur = CreateBoxShadow(*aDestDrawTarget, minMask, aShadowColor);
+  if (!minInsetBlur) {
+    return nullptr;
+  }
+
+  if (!aIsDestRect) {
+    CacheInsetBlur(outerSize, whitespaceSize,
+                   aBlurRadius, &aInnerClipRadii,
+                   aShadowColor, aHasBorderRadius,
+                   aDestDrawTarget->GetBackendType(),
+                   minInsetBlur);
+  }
+
+  return minInsetBlur.forget();
+}
+
+/***
+ * We create our minimal rect with 2 rects.
+ * The first is the inside whitespace rect, that is "cut out"
+ * from the box. This is (1). This must be the size
+ * of the blur radius + corner radius so we can have a big enough
+ * inside cut.
+ *
+ * The second (2) is one blur radius surrounding the inner
+ * frame of (1). This is the amount of blur space required
+ * to get a proper blend.
+ *
+ * B = one blur size
+ * W = one blur + corner radii - known as inner margin
+ * ___________________________________
+ * |                                |
+ * |          |             |       |
+ * |      (2) |    (1)      |  (2)  |
+ * |       B  |     W       |   B   |
+ * |          |             |       |
+ * |          |             |       |
+ * |          |                     |
+ * |________________________________|
+ */
+static void GetBlurMargins(const bool aHasBorderRadius,
+                           const RectCornerRadii& aInnerClipRadii,
+                           const IntSize aBlurRadius,
+                           Margin& aOutBlurMargin,
+                           Margin& aOutInnerMargin)
+{
+  float cornerWidth = 0;
+  float cornerHeight = 0;
+  if (aHasBorderRadius) {
+    for (size_t i = 0; i < 4; i++) {
+      cornerWidth = std::max(cornerWidth, aInnerClipRadii[i].width);
+      cornerHeight = std::max(cornerHeight, aInnerClipRadii[i].height);
+    }
+  }
+
+  // Only the inside whitespace size cares about the border radius size.
+  // Outer sizes only care about blur.
+  int width = cornerWidth + aBlurRadius.width;
+  int height = cornerHeight + aBlurRadius.height;
+
+  aOutInnerMargin.SizeTo(height, width, height, width);
+  aOutBlurMargin.SizeTo(aBlurRadius.height, aBlurRadius.width,
+                        aBlurRadius.height, aBlurRadius.width);
+}
+
+static bool
+GetInsetBoxShadowRects(const Margin aBlurMargin,
+                       const Margin aInnerMargin,
+                       const Rect aShadowClipRect,
+                       const Rect aDestinationRect,
+                       Rect& aOutWhitespaceRect,
+                       Rect& aOutOuterRect)
+{
+  // We always copy (2 * blur radius) + corner radius worth of data to the destination rect
+  // This covers the blend of the path + the actual blur
+  // Need +1 so that we copy the edges correctly as we'll copy
+  // over the min box shadow corners then the +1 for the edges between
+  // Note, the (x,y) coordinates are from the blur margin
+  // since the frame outside the whitespace rect is 1 blur radius extra space.
+  Rect insideWhiteSpace(aBlurMargin.left,
+                        aBlurMargin.top,
+                        aInnerMargin.LeftRight() + 1,
+                        aInnerMargin.TopBottom() + 1);
+
+  // If the inner white space rect is larger than the shadow clip rect
+  // our approach does not work as we'll just copy one corner
+  // and cover the destination. In those cases, fallback to the destination rect
+  bool useDestRect = (aShadowClipRect.width <= aInnerMargin.LeftRight()) ||
+                     (aShadowClipRect.height <= aInnerMargin.TopBottom());
+
+  if (useDestRect) {
+    aOutWhitespaceRect = aShadowClipRect;
+    aOutOuterRect = aDestinationRect;
+  } else {
+    aOutWhitespaceRect = insideWhiteSpace;
+    aOutOuterRect = aOutWhitespaceRect;
+    aOutOuterRect.Inflate(aBlurMargin);
+  }
+
+  return useDestRect;
+}
+
+void
+gfxAlphaBoxBlur::BlurInsetBox(gfxContext* aDestinationCtx,
+                              const Rect aDestinationRect,
+                              const Rect aShadowClipRect,
+                              const IntSize aBlurRadius,
+                              const IntSize aSpreadRadius,
+                              const Color& aShadowColor,
+                              bool aHasBorderRadius,
+                              const RectCornerRadii& aInnerClipRadii,
+                              const Rect aSkipRect,
+                              const Point aShadowOffset)
+{
+  if ((aBlurRadius.width == 0 && aBlurRadius.height == 0)
+      || aShadowClipRect.IsEmpty()) {
+    FillDestinationPath(aDestinationCtx, aDestinationRect, aShadowClipRect,
+        aShadowColor, aHasBorderRadius, aInnerClipRadii);
+    return;
+  }
+
+  DrawTarget* destDrawTarget = aDestinationCtx->GetDrawTarget();
+
+  Margin innerMargin;
+  Margin blurMargin;
+  GetBlurMargins(aHasBorderRadius, aInnerClipRadii, aBlurRadius,
+                 blurMargin, innerMargin);
+
+  Rect whitespaceRect;
+  Rect outerRect;
+  bool useDestRect = GetInsetBoxShadowRects(blurMargin, innerMargin, aShadowClipRect,
+                                            aDestinationRect, whitespaceRect, outerRect);
+
+  RefPtr<SourceSurface> minBlur = GetInsetBlur(outerRect, whitespaceRect, useDestRect, aShadowColor,
+                                               aBlurRadius, aHasBorderRadius, aInnerClipRadii,
+                                               destDrawTarget);
+  if (!minBlur) {
+    return;
+  }
+
+  if (useDestRect) {
+    IntSize blurSize = minBlur->GetSize();
+    Rect srcBlur(0, 0, blurSize.width, blurSize.height);
+    Rect destBlur = aDestinationRect;
+
+    // The blur itself expands the rect by the blur margin, so we
+    // have to mimic that here.
+    destBlur.Inflate(blurMargin);
+    MOZ_ASSERT(srcBlur.Size() == destBlur.Size());
+    destDrawTarget->DrawSurface(minBlur, destBlur, srcBlur);
+  } else {
+    Rect srcOuter(outerRect);
+    Rect srcInner(srcOuter);
+    srcInner.Deflate(blurMargin);   // The outer color fill
+    srcInner.Deflate(innerMargin);  // The inner whitespace
+
+    // The shadow clip rect already takes into account the spread radius
+    Rect outerFillRect(aShadowClipRect);
+    outerFillRect.Inflate(blurMargin);
+    FillDestinationPath(aDestinationCtx, aDestinationRect, outerFillRect, aShadowColor, false, RectCornerRadii());
+
+    // Inflate once for the frame around the whitespace
+    Rect destRect(aShadowClipRect);
+    destRect.Inflate(blurMargin);
+
+    // Deflate for the blurred in white space
+    Rect destInnerRect(aShadowClipRect);
+    destInnerRect.Deflate(innerMargin);
+
+    DrawBoxShadows(*destDrawTarget, minBlur,
+                   destRect, destInnerRect,
+                   srcOuter, srcInner,
+                   aSkipRect);
+  }
+}