Adds DevTools commands for forced viewport override.

third_party/WebKit/Source/core/frame/FrameView.h

Index: third_party/WebKit/Source/core/frame/FrameView.h
diff --git a/third_party/WebKit/Source/core/frame/FrameView.h b/third_party/WebKit/Source/core/frame/FrameView.h
index 55f071cafc334489d06d45c50113a5303dd18096..6b2d8ac793c3f8c35c40708ba83621417e26f072 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.h
+++ b/third_party/WebKit/Source/core/frame/FrameView.h
@@ -191,6 +191,7 @@ public:
     void setInputEventsTransformForEmulation(const IntSize&, float);
 
     void setScrollPosition(const DoublePoint&, ScrollType, ScrollBehavior = ScrollBehaviorInstant) override;
+    void didChangeScrollOffset();
 
     void didUpdateElasticOverscroll();
 
@@ -450,6 +451,11 @@ public:
     IntRect visibleContentRect(IncludeScrollbarsInRect = ExcludeScrollbars) const override;
     IntSize visibleContentSize(IncludeScrollbarsInRect = ExcludeScrollbars) const;
 
+    // Clips the provided rect to the visible content area. For this purpose, we
+    // also query the chrome client for any active overrides to the visible area
+    // (e.g. DevTool's viewport override).
+    void clipPaintRect(FloatRect*) const;
+
     // Functions for getting/setting the size of the document contained inside the FrameView (as an IntSize or as individual width and height
     // values).
     IntSize contentsSize() const override; // Always at least as big as the visibleWidth()/visibleHeight().
@@ -884,6 +890,7 @@ private:
     DoubleSize m_pendingScrollDelta;
     DoublePoint m_scrollPosition;
     IntSize m_contentsSize;
+    WTF::Optional<IntRect> m_visibleContentRectForPainting;

[dgozman, 2016/08/29 20:45:36]

Unused.

[Eric Seckler, 2016/09/12 13:58:00]

Done.

 
     int m_scrollbarsAvoidingResizer;
     bool m_scrollbarsSuppressed;