Support for drawing a debug border around animated layers

cc/debug/debug_rect_history.cc

Index: cc/debug/debug_rect_history.cc
diff --git a/cc/debug/debug_rect_history.cc b/cc/debug/debug_rect_history.cc
index b972b321d8dbecedffc70f07cd95443b43413731..5ce57092f56efcc71f5f6d83434d994c86b2164c 100644
--- a/cc/debug/debug_rect_history.cc
+++ b/cc/debug/debug_rect_history.cc
@@ -58,6 +58,9 @@ void DebugRectHistory::SaveDebugRectsForCurrentFrame(
 
   if (debug_state.show_non_occluding_rects)
     SaveNonOccludingRects(non_occluding_screen_space_rects);
+
+  if (debug_state.show_layer_animation_bounds_rects)
+    SaveLayerAnimationBoundsRects(render_surface_layer_list);
 }
 
 void DebugRectHistory::SavePaintRects(LayerImpl* layer) {
@@ -232,4 +235,32 @@ void DebugRectHistory::SaveNonFastScrollableRectsCallback(LayerImpl* layer) {
   }
 }
 
+void DebugRectHistory::SaveLayerAnimationBoundsRects(
+    const LayerImplList& render_surface_layer_list) {
+  for (int surface_index = render_surface_layer_list.size() - 1;
+       surface_index >= 0;
+       --surface_index) {
+    LayerImpl* render_surface_layer = render_surface_layer_list[surface_index];
+    RenderSurfaceImpl* render_surface = render_surface_layer->render_surface();
+    DCHECK(render_surface);
+
+    const LayerImplList& layer_list = render_surface->layer_list();
+    for (unsigned layer_index = 0;
+         layer_index < layer_list.size();
+         ++layer_index) {
+      LayerImpl* layer = layer_list[layer_index];
+
+      gfx::BoxF inflated_bounds;
+      if (!layer->GetAnimationBounds(&inflated_bounds))
+        continue;
+
+      debug_rects_.push_back(DebugRect(ANIMATION_BOUNDS_RECT_TYPE,
+                                       gfx::RectF(inflated_bounds.x(),
+                                                  inflated_bounds.y(),
+                                                  inflated_bounds.width(),
+                                                  inflated_bounds.height())));
+    }
+  }
+}
+
 }  // namespace cc