WIP - Gutterless resize on Windows

ui/compositor/compositor.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_COMPOSITOR_COMPOSITOR_H_
 #define UI_COMPOSITOR_COMPOSITOR_H_
 
 #include <string>
 
 #include "base/containers/hash_tables.h"
@@ skipping 306 matching lines @@
   const cc::RendererSettings& GetRendererSettings() const;
 
   LayerAnimatorCollection* layer_animator_collection() {
     return &layer_animator_collection_;
   }
 
   cc::SurfaceIdAllocator* surface_id_allocator() {
     return surface_id_allocator_.get();
   }
 
+  gfx::Size last_swapped_frame_size() const { return last_swapped_frame_size_; }
+
  private:
   friend class base::RefCounted<Compositor>;
   friend class CompositorLock;
+  class ResizeSwapPromise;
 
   // Called by CompositorLock.
   void UnlockCompositor();
 
   // Called to release any pending CompositorLock
   void CancelCompositorLock();
 
+  void set_pending_swapped_frame_size(
+      const gfx::Size& pending_swapped_frame_size) {
+    pending_swapped_frame_size_ = pending_swapped_frame_size;
+  }
+
+  void UpdateLastSwappedFrameSize() {
+    last_swapped_frame_size_ = pending_swapped_frame_size_;
+    pending_swapped_frame_size_ = gfx::Size();
+  }
+
   gfx::Size size_;
 
   ui::ContextFactory* context_factory_;
 
   // The root of the Layer tree drawn by this compositor.
   Layer* root_layer_;
 
   base::ObserverList<CompositorObserver, true> observer_list_;
   base::ObserverList<CompositorAnimationObserver> animation_observer_list_;
   base::ObserverList<CompositorBeginFrameObserver, true>
@@ skipping 18 matching lines @@
   int last_ended_frame_;
 
   bool locks_will_time_out_;
   CompositorLock* compositor_lock_;
 
   LayerAnimatorCollection layer_animator_collection_;
 
   // Used to send to any new CompositorBeginFrameObserver immediately.
   cc::BeginFrameArgs missed_begin_frame_args_;
 
+  // Used to track the last swapped frame size. We use a swap promise to track
+  // the progression of a frame through resizing of the compositor to posting
+  // swap buffers. Once posted, the frame's size is recorded to
+  // |pending_swapped_frame_size_|. Once a swap completes, the pending size is
+  // promoted to the |last_swapped_frame_size_|.
+  gfx::Size last_swapped_frame_size_;
+  gfx::Size pending_swapped_frame_size_;
+
   base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_