Add hints for potential overlay promotion on android.

cc/output/overlay_strategy_underlay.cc

 // Copyright 2014 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_underlay.h"
 
 #include "cc/output/overlay_candidate_validator.h"
 #include "cc/quads/draw_quad.h"
 #include "cc/quads/solid_color_draw_quad.h"
 
@@ skipping 29 matching lines @@
     if (new_candidate_list.back().overlay_handled) {
       new_candidate_list.back().is_unoccluded =
           !OverlayCandidate::IsOccluded(candidate, quad_list.cbegin(), it);
       const SharedQuadState* shared_quad_state = it->shared_quad_state;
       gfx::Rect rect = it->visible_rect;
       SolidColorDrawQuad* replacement =
           quad_list.ReplaceExistingElement<SolidColorDrawQuad>(it);
       replacement->SetAll(shared_quad_state, rect, rect, rect, false,
                           SK_ColorTRANSPARENT, true);
       candidate_list->swap(new_candidate_list);
+
+      // This quad will be promoted.  We clear the promotable hints here, since
+      // we can only promote a single quad.  Otherwise, somebody might try to
+      // back one of the promotable quads with a SurfaceView, and either it or
+      // |candidate| would have to fall back to a texture.
+      candidate_list->promotable_resource_hints_.clear();
+      candidate_list->promotable_resource_hints_.insert(candidate.resource_id);
       return true;
+    } else {
+      // If |candidate| should get a promotion hint, then rememeber that now.
+      candidate_list->promotable_resource_hints_.insert(
+          new_candidate_list.promotable_resource_hints_.begin(),
+          new_candidate_list.promotable_resource_hints_.end());
     }
   }
 
   return false;
 }
 
 }  // namespace cc