WIP - Gutterless resize on Windows

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index 1602d30caae8b7b4ad72f727422e309428722004..7be892db54370c2d45daaabdc057227b1e1f12e4 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -324,6 +324,11 @@ class COMPOSITOR_EXPORT Compositor
     return surface_id_allocator_.get();
   }
 
+  // Returns true if the compositor has swapped a frame since being resized.
+  bool has_swapped_frame_at_current_size() const {
+    return has_swapped_frame_at_current_size_;
+  }
+
  private:
   friend class base::RefCounted<Compositor>;
   friend class CompositorLock;
@@ -372,6 +377,8 @@ class COMPOSITOR_EXPORT Compositor
   // Used to send to any new CompositorBeginFrameObserver immediately.
   cc::BeginFrameArgs missed_begin_frame_args_;
 
+  bool has_swapped_frame_at_current_size_;
+
   base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);