Made PinchViewport a ScrollableArea

Source/platform/graphics/GraphicsLayer.cpp

Index: Source/platform/graphics/GraphicsLayer.cpp
diff --git a/Source/platform/graphics/GraphicsLayer.cpp b/Source/platform/graphics/GraphicsLayer.cpp
index 310f49aa6fdae87b1f5245f47aba0d33c7c9498d..26de763f247efa2326063a0c033bda30e885192e 100644
--- a/Source/platform/graphics/GraphicsLayer.cpp
+++ b/Source/platform/graphics/GraphicsLayer.cpp
@@ -1182,6 +1182,8 @@ void GraphicsLayer::setScrollableArea(ScrollableArea* scrollableArea, bool isMai
 
     // Main frame scrolling may involve pinch zoom and gets routed through
     // WebViewImpl explicitly rather than via GraphicsLayer::didScroll.
+    // TODO(bokan): With pinch virtual viewport the special case will no

[aelias_OOO_until_Jul13, 2014/03/24 21:47:24]

Could you make this conditional on the pinchVirtualViewport flag being false
instead?

[bokan, 2014/03/24 23:36:30]

The isMainFrame argument is conditional on that flag when this method is
called in ScrollingCoordinator. Did you want me to move that condition
into here?

[aelias_OOO_until_Jul13, 2014/03/25 00:05:48]

Yes, I think that would make more sense.  Since it's still the main frame, the
current implementation is lying to this method.

[bokan, 2014/03/25 00:54:42]

It doesn't look like there's any hooks in GraphicsLayer into anything that has
Settings/WebSettings so I don't think I can do this without introducing some
layering violations. I could make this method take the setting's value in
another argument but that feels awkward -- I could change isMainFrame to
scrollsCallGraphicsLayerDidScroll or similar. What's your preference?

[aelias_OOO_until_Jul13, 2014/03/25 01:09:00]

OK, whatever, the TODO is fine then.  No big deal as long as we delete it later.

+    // longer be needed, remove once old-style pinch is gone.
     if (isMainFrame)
         m_layer->layer()->setScrollClient(0);
     else