Add CompositingReasons to compositor layers.

cc/layers/layer.cc

 // Copyright 2010 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.
 
 #include "cc/layers/layer.h"
 
 #include <algorithm>
 
 #include "base/metrics/histogram.h"
 #include "cc/animation/animation.h"
@@ skipping 22 matching lines @@
       stacking_order_changed_(false),
       layer_id_(s_next_layer_id++),
       ignore_set_needs_commit_(false),
       parent_(NULL),
       layer_tree_host_(NULL),
       scrollable_(false),
       should_scroll_on_main_thread_(false),
       have_wheel_event_handlers_(false),
       anchor_point_(0.5f, 0.5f),
       background_color_(0),
+      compositing_reasons_(kCompositingReasonUnknown),
       opacity_(1.f),
       anchor_point_z_(0.f),
       is_container_for_fixed_position_layers_(false),
       is_drawable_(false),
       masks_to_bounds_(false),
       contents_opaque_(false),
       double_sided_(true),
       preserves_3d_(false),
       use_parent_backface_visibility_(false),
       draw_checkerboard_for_missing_tiles_(false),
@@ skipping 583 matching lines @@
 }
 
 void Layer::PushPropertiesTo(LayerImpl* layer) {
   layer->SetAnchorPoint(anchor_point_);
   layer->SetAnchorPointZ(anchor_point_z_);
   layer->SetBackgroundColor(background_color_);
   layer->SetBounds(paint_properties_.bounds);
   layer->SetContentBounds(content_bounds());
   layer->SetContentsScale(contents_scale_x(), contents_scale_y());
   layer->SetDebugName(debug_name_);
+  layer->SetCompositingReasons(compositing_reasons_);
   layer->SetDoubleSided(double_sided_);
   layer->SetDrawCheckerboardForMissingTiles(
       draw_checkerboard_for_missing_tiles_);
   layer->SetForceRenderSurface(force_render_surface_);
   layer->SetDrawsContent(DrawsContent());
   layer->SetFilters(filters());
   layer->SetFilter(filter());
   layer->SetBackgroundFilters(background_filters());
   layer->SetMasksToBounds(masks_to_bounds_);
   layer->SetShouldScrollOnMainThread(should_scroll_on_main_thread_);
@@ skipping 86 matching lines @@
 
 bool Layer::NeedMoreUpdates() {
   return false;
 }
 
 void Layer::SetDebugName(const std::string& debug_name) {
   debug_name_ = debug_name;
   SetNeedsCommit();
 }
 
+void Layer::SetCompositingReasons(CompositingReasons reasons) {
+  // For now this is only debug information, so we avoid calling
+  // SetNeedsCommit() which causes invalidations in some code paths.

[jamesr, 2013/05/28 23:20:05]

Do you expect this to become something other than debug information in the
future?

+  compositing_reasons_ = reasons;
+}
+
 void Layer::CreateRenderSurface() {
   DCHECK(!draw_properties_.render_surface);
   draw_properties_.render_surface = make_scoped_ptr(new RenderSurface(this));
   draw_properties_.render_target = this;
 }
 
 void Layer::ClearRenderSurface() {
   draw_properties_.render_surface.reset();
 }
 
@@ skipping 88 matching lines @@
 
 RenderingStatsInstrumentation* Layer::rendering_stats_instrumentation() const {
   return layer_tree_host_->rendering_stats_instrumentation();
 }
 
 bool Layer::SupportsLCDText() const {
   return false;
 }
 
 }  // namespace cc