Overlays: Remove special casing of primary overlay plane

cc/output/overlay_strategy_common.cc

 // Copyright 2015 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/overlay_strategy_common.h"
 
 #include <limits>
 
 #include "cc/base/math_util.h"
 #include "cc/quads/io_surface_draw_quad.h"
@@ skipping 16 matching lines @@
 }
 
 bool OverlayStrategyCommon::Attempt(RenderPassList* render_passes_in_draw_order,
                                     OverlayCandidateList* candidate_list,
                                     float device_scale_factor) {
   if (!capability_checker_)
     return false;
   RenderPass* root_render_pass = render_passes_in_draw_order->back();
   DCHECK(root_render_pass);
 
-  // Add our primary surface.
-  OverlayCandidate main_image;
-  main_image.display_rect = gfx::RectF(root_render_pass->output_rect);
-  DCHECK(candidate_list->empty());
-  candidate_list->push_back(main_image);
-
   bool created_overlay = false;
   QuadList& quad_list = root_render_pass->quad_list;
   for (auto it = quad_list.begin(); it != quad_list.end();) {
     OverlayCandidate candidate;
     if (!GetCandidateQuadInfo(**it, &candidate)) {
       ++it;
       continue;
     }
 
     OverlayResult result = delegate_->TryOverlay(
         capability_checker_, render_passes_in_draw_order, candidate_list,
         candidate, &it, device_scale_factor);
     switch (result) {
       case DID_NOT_CREATE_OVERLAY:
         ++it;
         break;
       case CREATED_OVERLAY_STOP_LOOKING:
         return true;
       case CREATED_OVERLAY_KEEP_LOOKING:
         created_overlay = true;
         break;
     }
   }
 
-  if (!created_overlay) {
-    DCHECK_EQ(1u, candidate_list->size());
-    candidate_list->clear();
-  }
-
   return created_overlay;
 }
 
 // static
 bool OverlayStrategyCommon::IsInvisibleQuad(const DrawQuad* draw_quad) {
   if (draw_quad->material == DrawQuad::SOLID_COLOR) {
     const SolidColorDrawQuad* solid_quad =
         SolidColorDrawQuad::MaterialCast(draw_quad);
     SkColor color = solid_quad->color;
     float opacity = solid_quad->shared_quad_state->opacity;
@@ skipping 114 matching lines @@
   quad_info->display_rect = OverlayCandidate::GetOverlayRect(
       draw_quad.shared_quad_state->quad_to_target_transform, draw_quad.rect);
   quad_info->quad_rect_in_target_space = MathUtil::MapEnclosingClippedRect(
       draw_quad.shared_quad_state->quad_to_target_transform, draw_quad.rect);
   quad_info->clip_rect = draw_quad.shared_quad_state->clip_rect;
   quad_info->is_clipped = draw_quad.shared_quad_state->is_clipped;
   return true;
 }
 
 }  // namespace cc