Update from https://crrev.com/316786

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 232913933965f14c223c1ba7e83579783ebdecad..54c86604d3435edd63f9d5343787185d09307400 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -22,13 +22,7 @@ namespace base {
 namespace trace_event {
 class TracedValue;
 }
-
-// TODO(ssid): remove these aliases after the tracing clients are moved to the
-// new trace_event namespace. See crbug.com/451032. ETA: March 2015
-namespace debug {
-using ::base::trace_event::TracedValue;
 }
-}  // namespace base
 
 namespace cc {
 
@@ -55,6 +49,7 @@ struct RendererCapabilities;
 struct SelectionHandle;
 
 typedef std::vector<UIResourceRequest> UIResourceRequestQueue;
+typedef SyncedProperty<AdditionGroup<float>> SyncedTopControls;
 typedef SyncedProperty<AdditionGroup<gfx::Vector2dF>> SyncedElasticOverscroll;
 
 class CC_EXPORT LayerTreeImpl {
@@ -62,9 +57,11 @@ class CC_EXPORT LayerTreeImpl {
   static scoped_ptr<LayerTreeImpl> create(
       LayerTreeHostImpl* layer_tree_host_impl,
       scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
+      scoped_refptr<SyncedTopControls> top_controls_shown_ratio,
       scoped_refptr<SyncedElasticOverscroll> elastic_overscroll) {
-    return make_scoped_ptr(new LayerTreeImpl(
-        layer_tree_host_impl, page_scale_factor, elastic_overscroll));
+    return make_scoped_ptr(
+        new LayerTreeImpl(layer_tree_host_impl, page_scale_factor,
+                          top_controls_shown_ratio, elastic_overscroll));
   }
   virtual ~LayerTreeImpl();
 
@@ -75,6 +72,7 @@ class CC_EXPORT LayerTreeImpl {
   // Methods called by the layer tree that pass-through or access LTHI.
   // ---------------------------------------------------------------------------
   const LayerTreeSettings& settings() const;
+  const LayerTreeDebugState& debug_state() const;
   const RendererCapabilitiesImpl& GetRendererCapabilities() const;
   ContextProvider* context_provider() const;
   OutputSurface* output_surface() const;
@@ -84,6 +82,8 @@ class CC_EXPORT LayerTreeImpl {
   PaintTimeCounter* paint_time_counter() const;
   MemoryHistory* memory_history() const;
   gfx::Size device_viewport_size() const;
+  float device_scale_factor() const;
+  DebugRectHistory* debug_rect_history() const;
   bool IsActiveTree() const;
   bool IsPendingTree() const;
   bool IsRecycleTree() const;
@@ -111,13 +111,10 @@ class CC_EXPORT LayerTreeImpl {
   // ---------------------------------------------------------------------------
   void SetNeedsRedraw();
 
-  // TODO(nduca): These are implemented in cc files temporarily, but will become
-  // trivial accessors in a followup patch.
-  const LayerTreeDebugState& debug_state() const;
-  float device_scale_factor() const;
-  DebugRectHistory* debug_rect_history() const;
+  // Tracing methods.
+  // ---------------------------------------------------------------------------
   void GetAllTilesForTracing(std::set<const Tile*>* tiles) const;
-  void AsValueInto(base::debug::TracedValue* dict) const;
+  void AsValueInto(base::trace_event::TracedValue* dict) const;
 
   // Other public methods
   // ---------------------------------------------------------------------------
@@ -192,6 +189,13 @@ class CC_EXPORT LayerTreeImpl {
     return elastic_overscroll_.get();
   }
 
+  SyncedTopControls* top_controls_shown_ratio() {
+    return top_controls_shown_ratio_.get();
+  }
+  const SyncedTopControls* top_controls_shown_ratio() const {
+    return top_controls_shown_ratio_.get();
+  }
+
   // Updates draw properties and render surface layer list, as well as tile
   // priorities. Returns false if it was unable to update.
   bool UpdateDrawProperties();
@@ -216,6 +220,7 @@ class CC_EXPORT LayerTreeImpl {
   void set_ui_resource_request_queue(const UIResourceRequestQueue& queue);
 
   const LayerImplList& RenderSurfaceLayerList() const;
+  const Region& UnoccludedScreenSpaceRegion() const;
 
   // These return the size of the root scrollable area and the size of
   // the user-visible scrolling viewport, in CSS layout coordinates.
@@ -273,6 +278,12 @@ class CC_EXPORT LayerTreeImpl {
 
   bool IsUIResourceOpaque(UIResourceId uid) const;
 
+  void RegisterPictureLayerImpl(PictureLayerImpl* layer);
+  void UnregisterPictureLayerImpl(PictureLayerImpl* layer);
+  const std::vector<PictureLayerImpl*>& picture_layers() const {
+    return picture_layers_;
+  }
+
   void AddLayerWithCopyOutputRequest(LayerImpl* layer);
   void RemoveLayerWithCopyOutputRequest(LayerImpl* layer);
   const std::vector<LayerImpl*>& LayersWithCopyOutputRequest() const;
@@ -300,39 +311,17 @@ class CC_EXPORT LayerTreeImpl {
   void GetViewportSelection(ViewportSelectionBound* start,
                             ViewportSelectionBound* end);
 
-  void RegisterPictureLayerImpl(PictureLayerImpl* layer);
-  void UnregisterPictureLayerImpl(PictureLayerImpl* layer);
-
-  void set_top_controls_shrink_blink_size(bool shrink) {
-    top_controls_shrink_blink_size_ = shrink;
-  }
-  void set_top_controls_height(float height) { top_controls_height_ = height; }
-  void set_top_controls_content_offset(float offset) {
-    top_controls_content_offset_ = offset;
-  }
-  void set_top_controls_delta(float delta) {
-    top_controls_delta_ = delta;
-  }
-  void set_sent_top_controls_delta(float sent_delta) {
-    sent_top_controls_delta_ = sent_delta;
-  }
-
+  void set_top_controls_shrink_blink_size(bool shrink);
   bool top_controls_shrink_blink_size() const {
     return top_controls_shrink_blink_size_;
   }
-  float top_controls_height() const { return top_controls_height_; }
-  float top_controls_content_offset() const {
-    return top_controls_content_offset_;
-  }
-  float top_controls_delta() const {
-    return top_controls_delta_;
-  }
-  float sent_top_controls_delta() const {
-    return sent_top_controls_delta_;
-  }
-  float total_top_controls_content_offset() const {
-    return top_controls_content_offset_ + top_controls_delta_;
+  bool SetCurrentTopControlsShownRatio(float ratio);
+  float CurrentTopControlsShownRatio() const {
+    return top_controls_shown_ratio_->Current(IsActiveTree());
   }
+  void set_top_controls_height(float top_controls_height);
+  float top_controls_height() const { return top_controls_height_; }
+  void PushTopControlsFromMainThread(float top_controls_shown_ratio);
 
   void SetPendingPageScaleAnimation(
       scoped_ptr<PendingPageScaleAnimation> pending_animation);
@@ -342,6 +331,7 @@ class CC_EXPORT LayerTreeImpl {
   explicit LayerTreeImpl(
       LayerTreeHostImpl* layer_tree_host_impl,
       scoped_refptr<SyncedProperty<ScaleGroup>> page_scale_factor,
+      scoped_refptr<SyncedTopControls> top_controls_shown_ratio,
       scoped_refptr<SyncedElasticOverscroll> elastic_overscroll);
   void ProcessLayersRecursive(LayerImpl* current,
                               void (LayerImpl::*function)());
@@ -353,7 +343,7 @@ class CC_EXPORT LayerTreeImpl {
                                 float max_page_scale_factor);
   void DidUpdatePageScale();
   void HideInnerViewportScrollbarsIfNearMinimumScale();
-
+  void PushTopControls(const float* top_controls_shown_ratio);
   LayerTreeHostImpl* layer_tree_host_impl_;
   int source_frame_number_;
   scoped_ptr<LayerImpl> root_layer_;
@@ -384,6 +374,7 @@ class CC_EXPORT LayerTreeImpl {
   typedef base::hash_map<int, LayerImpl*> LayerIdMap;
   LayerIdMap layer_id_map_;
 
+  std::vector<PictureLayerImpl*> picture_layers_;
   std::vector<LayerImpl*> layers_with_copy_output_request_;
 
   // Persisted state for non-impl-side-painting.
@@ -391,6 +382,9 @@ class CC_EXPORT LayerTreeImpl {
 
   // List of visible layers for the most recently prepared frame.
   LayerImplList render_surface_layer_list_;
+  // After drawing the |render_surface_layer_list_| the areas in this region
+  // would not be fully covered by opaque content.
+  Region unoccluded_screen_space_region_;
 
   bool contents_textures_purged_;
   bool viewport_size_invalid_;
@@ -416,11 +410,9 @@ class CC_EXPORT LayerTreeImpl {
 
   float top_controls_height_;
 
-  // The up-to-date content offset of the top controls, i.e. the amount that the
-  // web contents have been shifted down from the top of the device viewport.
-  float top_controls_content_offset_;
-  float top_controls_delta_;
-  float sent_top_controls_delta_;
+  // The amount that the top controls are shown from 0 (hidden) to 1 (fully
+  // shown).
+  scoped_refptr<SyncedTopControls> top_controls_shown_ratio_;
 
   scoped_ptr<PendingPageScaleAnimation> pending_page_scale_animation_;