Make new-style page scale work on Android.

cc/pinch_zoom_viewport.h

Index: cc/pinch_zoom_viewport.h
diff --git a/cc/pinch_zoom_viewport.h b/cc/pinch_zoom_viewport.h
index 0b55a3fe97df425ff9806172abb22739a1e92221..31bd2a4ddc9c6ef6f367362e031edd42325c38d0 100644
--- a/cc/pinch_zoom_viewport.h
+++ b/cc/pinch_zoom_viewport.h
@@ -47,9 +47,10 @@ class CC_EXPORT PinchZoomViewport {
                                    float min_page_scale_factor,
                                    float max_page_scale_factor);
 
-  // Returns the bounds and offset of the scaled and translated viewport to use
-  // for pinch-zoom.
-  gfx::RectF Bounds() const;
+  // Returns the zoomed viewport in layout space. The rect's position is an
+  // offset from the root layer's scroll position (therefore, zero if fully
+  // zoomed out).
+  gfx::RectF ZoomedViewport() const;
 
   const gfx::Vector2dF& zoomed_viewport_offset() const {
     return zoomed_viewport_offset_;
@@ -58,6 +59,9 @@ class CC_EXPORT PinchZoomViewport {
   void set_layout_viewport_size(const gfx::SizeF& size) {
     layout_viewport_size_ = size;
   }
+  void set_device_viewport_size(const gfx::SizeF& size) {

[wjmaclean, 2013/01/17 19:45:52]

Perhaps add a comment explaining why we need to store this, as opposed to just
converting layout_viewport_size_ using psf and dsf. 

[aelias_OOO_until_Jul13, 2013/01/17 19:59:46]

Done.

+    device_viewport_size_ = size;
+  }
 
   // Apply the scroll offset in layout space to the offset of the pinch-zoom
   // viewport. The viewport cannot be scrolled outside of the layout viewport
@@ -81,6 +85,7 @@ class CC_EXPORT PinchZoomViewport {
 
   gfx::Vector2dF zoomed_viewport_offset_;
   gfx::SizeF layout_viewport_size_;
+  gfx::SizeF device_viewport_size_;
 };
 
 }  // namespace cc