Ensure RemoteViewportIntersection rect persists across frame navigations

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

Index: third_party/WebKit/Source/core/frame/LocalFrame.h
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.h b/third_party/WebKit/Source/core/frame/LocalFrame.h
index d29aea93f4fc45ca49f5bbc9166070b8e65e7dbd..f49e7d0995ddd052064c685dfe1d0ebf892cfdf9 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.h
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.h
@@ -255,6 +255,12 @@ class CORE_EXPORT LocalFrame final : public Frame,
   // focused element or passed node into explicit methods.
   WebPluginContainerBase* GetWebPluginContainerBase(Node* = nullptr) const;
 
+  // Called on a view for a LocalFrame with a RemoteFrame parent. This makes
+  // viewport intersection available that accounts for remote ancestor frames
+  // and their respective scroll positions, clips, etc.
+  void SetViewportIntersectionFromParent(const IntRect&);
+  IntRect RemoteViewportIntersection() { return remote_viewport_intersection_; }
+
  private:
   friend class FrameNavigationDisabler;
 
@@ -305,6 +311,8 @@ class CORE_EXPORT LocalFrame final : public Frame,
 
   InterfaceProvider* const interface_provider_;
   InterfaceRegistry* const interface_registry_;
+
+  IntRect remote_viewport_intersection_;

[dcheng, 2017/05/30 19:54:11]

It feels a little weird to have layout information on the LocalFrame, but I
guess you could argue it's similar-ish to zoom factors.

[kenrb, 2017/05/30 21:19:21]

Similar idea, yes. I think frame-specific values that are set from external to
Blink end up needing to live on LocalFrame, even if they are inputs to layout or
painting, since LocalFrame survives navigations but LocalFrameView does not.

 };
 
 inline FrameLoader& LocalFrame::Loader() const {