Tag TransportDIBs with the device scale factor they expect.

content/browser/renderer_host/backing_store.h

Index: content/browser/renderer_host/backing_store.h
diff --git a/content/browser/renderer_host/backing_store.h b/content/browser/renderer_host/backing_store.h
index 580616a617a5fbcf58c9b5f973121509189a1118..391c0ffc199800ea89ca561f858c8ad98a6a794a 100644
--- a/content/browser/renderer_host/backing_store.h
+++ b/content/browser/renderer_host/backing_store.h
@@ -47,7 +47,9 @@ class CONTENT_EXPORT BackingStore {
 
   // Paints the bitmap from the renderer onto the backing store.  bitmap_rect

[Avi (use Gerrit), 2012/06/13 20:44:40]

One space after period to match rest of comment.

[Nico, 2012/06/13 20:46:58]

Done.

   // gives the location of bitmap, and copy_rects specifies the subregion(s) of
-  // the backingstore to be painted from the bitmap.
+  // the backingstore to be painted from the bitmap. All coordinates are in
+  // DIPs. |scale_factor| contains the expected device scale factor of the
+  // backing store.
   //
   // PaintToBackingStore does not need to guarantee that this has happened by
   // the time it returns, in which case it will set |scheduled_callback| to
@@ -57,6 +59,7 @@ class CONTENT_EXPORT BackingStore {
       TransportDIB::Id bitmap,
       const gfx::Rect& bitmap_rect,
       const std::vector<gfx::Rect>& copy_rects,
+      float scale_factor,
       const base::Closure& completion_callback,
       bool* scheduled_completion_callback) = 0;