1 files changed, 108 insertions, 0 deletions
diff --git a/layout/generic/nsViewportFrame.h b/layout/generic/nsViewportFrame.h
new file mode 100644
index 000000000..062de4054
--- /dev/null
+++ b/layout/generic/nsViewportFrame.h
@@ -0,0 +1,108 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+/*
+ * rendering object that is the root of the frame tree, which contains
+ * the document's scrollbars and contains fixed-positioned elements
+ */
+
+#ifndef nsViewportFrame_h___
+#define nsViewportFrame_h___
+
+#include "mozilla/Attributes.h"
+#include "nsContainerFrame.h"
+
+class nsPresContext;
+
+/**
+  * ViewportFrame is the parent of a single child - the doc root frame or a scroll frame
+  * containing the doc root frame. ViewportFrame stores this child in its primary child
+  * list.
+  */
+class ViewportFrame : public nsContainerFrame {
+public:
+  NS_DECL_QUERYFRAME_TARGET(ViewportFrame)
+  NS_DECL_QUERYFRAME
+  NS_DECL_FRAMEARENA_HELPERS
+
+  explicit ViewportFrame(nsStyleContext* aContext)
+    : nsContainerFrame(aContext)
+  {}
+  virtual ~ViewportFrame() { } // useful for debugging
+
+  virtual void Init(nsIContent*       aContent,
+                    nsContainerFrame* aParent,
+                    nsIFrame*         aPrevInFlow) override;
+
+  virtual mozilla::WritingMode GetWritingMode() const override
+  {
+    nsIFrame* firstChild = mFrames.FirstChild();
+    if (firstChild) {
+      return firstChild->GetWritingMode();
+    }
+    return nsIFrame::GetWritingMode();
+  }
+
+#ifdef DEBUG
+  virtual void AppendFrames(ChildListID     aListID,
+                            nsFrameList&    aFrameList) override;
+  virtual void InsertFrames(ChildListID     aListID,
+                            nsIFrame*       aPrevFrame,
+                            nsFrameList&    aFrameList) override;
+  virtual void RemoveFrame(ChildListID     aListID,
+                           nsIFrame*       aOldFrame) override;
+#endif
+
+  virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
+                                const nsRect&           aDirtyRect,
+                                const nsDisplayListSet& aLists) override;
+
+  void BuildDisplayListForTopLayer(nsDisplayListBuilder* aBuilder,
+                                   nsDisplayList* aList);
+
+  virtual nscoord GetMinISize(nsRenderingContext *aRenderingContext) override;
+  virtual nscoord GetPrefISize(nsRenderingContext *aRenderingContext) override;
+  virtual void Reflow(nsPresContext*           aPresContext,
+                      ReflowOutput&     aDesiredSize,
+                      const ReflowInput& aReflowInput,
+                      nsReflowStatus&          aStatus) override;
+
+  /**
+   * Get the "type" of the frame
+   *
+   * @see nsGkAtoms::viewportFrame
+   */
+  virtual nsIAtom* GetType() const override;
+
+  virtual bool ComputeCustomOverflow(nsOverflowAreas& aOverflowAreas) override;
+
+  /**
+   * Adjust aReflowInput to account for scrollbars and pres shell
+   * GetScrollPositionClampingScrollPortSizeSet and
+   * GetContentDocumentFixedPositionMargins adjustments.
+   * @return the rect to use as containing block rect
+   */
+  nsRect AdjustReflowInputAsContainingBlock(ReflowInput* aReflowInput) const;
+
+#ifdef DEBUG_FRAME_DUMP
+  virtual nsresult GetFrameName(nsAString& aResult) const override;
+#endif
+
+private:
+  virtual mozilla::layout::FrameChildListID GetAbsoluteListID() const override { return kFixedList; }
+
+protected:
+  /**
+   * Calculate how much room is available for fixed frames. That means
+   * determining if the viewport is scrollable and whether the vertical and/or
+   * horizontal scrollbars are visible.  Adjust the computed width/height and
+   * available width for aReflowInput accordingly.
+   * @return the current scroll position, or 0,0 if not scrollable
+   */
+  nsPoint AdjustReflowInputForScrollbars(ReflowInput* aReflowInput) const;
+};
+
+
+#endif // nsViewportFrame_h___