cc: Implement overdraw feedback debugging feature.

cc/output/direct_renderer.cc

 // Copyright 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.
 
 #include "cc/output/direct_renderer.h"
 
 #include <stddef.h>
 
 #include <unordered_map>
 #include <utility>
@@ skipping 69 matching lines @@
   overlay_processor_->Initialize();
 
   auto* context_provider = output_surface_->context_provider();
 
   use_partial_swap_ = settings_->partial_swap_enabled && CanPartialSwap();
   allow_empty_swap_ = use_partial_swap_;
   if (context_provider &&
       context_provider->ContextCapabilities().commit_overlay_planes)
     allow_empty_swap_ = true;
 
+  overdraw_feedback_ = settings_->overdraw_feedback &&
+                       output_surface_->capabilities().supports_stencil;
+  LOG_IF(WARNING, overdraw_feedback_ != settings_->overdraw_feedback)
+      << "Overdraw feedback enabled without output surface stencil support.";
+
   initialized_ = true;
 }
 
 // static
 gfx::RectF DirectRenderer::QuadVertexRect() {
   return gfx::RectF(-0.5f, -0.5f, 1.f, 1.f);
 }
 
 // static
 void DirectRenderer::QuadRectTransform(gfx::Transform* quad_rect_transform,
@@ skipping 131 matching lines @@
   frame.root_damage_rect = root_render_pass->damage_rect;
   frame.root_damage_rect.Union(overlay_processor_->GetAndResetOverlayDamage());
   frame.root_damage_rect.Intersect(gfx::Rect(device_viewport_size));
   frame.device_viewport_size = device_viewport_size;
   frame.device_color_space = device_color_space;
 
   // Only reshape when we know we are going to draw. Otherwise, the reshape
   // can leave the window at the wrong size if we never draw and the proper
   // viewport size is never set.
   bool frame_has_alpha = frame.root_render_pass->has_transparent_background;
+  bool use_stencil = overdraw_feedback_;
   if (device_viewport_size != reshape_surface_size_ ||
       device_scale_factor != reshape_device_scale_factor_ ||
       device_color_space != reshape_device_color_space_ ||
       frame_has_alpha != reshape_has_alpha_) {
     reshape_surface_size_ = device_viewport_size;
     reshape_device_scale_factor_ = device_scale_factor;
     reshape_device_color_space_ = device_color_space;
     reshape_has_alpha_ = frame.root_render_pass->has_transparent_background;
-    output_surface_->Reshape(reshape_surface_size_,
-                             reshape_device_scale_factor_,
-                             reshape_device_color_space_, reshape_has_alpha_);
+    output_surface_->Reshape(
+        reshape_surface_size_, reshape_device_scale_factor_,
+        reshape_device_color_space_, reshape_has_alpha_, use_stencil);
   }
 
   BeginDrawingFrame(&frame);
 
   for (const auto& pass : *render_passes_in_draw_order) {
     if (!pass->filters.IsEmpty())
       render_pass_filters_.push_back(std::make_pair(pass->id, &pass->filters));
     if (!pass->background_filters.IsEmpty()) {
       render_pass_background_filters_.push_back(
           std::make_pair(pass->id, &pass->background_filters));
@@ skipping 346 matching lines @@
   auto iter = render_pass_textures_.find(render_pass_id);
   return iter != render_pass_textures_.end() && iter->second->id();
 }
 
 // static
 gfx::Size DirectRenderer::RenderPassTextureSize(const RenderPass* render_pass) {
   return render_pass->output_rect.size();
 }
 
 }  // namespace cc