Add hints for potential overlay promotion on android.

cc/output/overlay_processor.cc

Index: cc/output/overlay_processor.cc
diff --git a/cc/output/overlay_processor.cc b/cc/output/overlay_processor.cc
index 7996ce6789f5c0eb20c6acb1641848028a149cfd..a9ecda698f9d9ae9b657a89e6cb7c1b4096d14f8 100644
--- a/cc/output/overlay_processor.cc
+++ b/cc/output/overlay_processor.cc
@@ -8,9 +8,34 @@
 #include "cc/output/overlay_strategy_single_on_top.h"
 #include "cc/output/overlay_strategy_underlay.h"
 #include "cc/quads/draw_quad.h"
+#include "cc/resources/resource_provider.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/transform.h"
 
+namespace {
+
+// Utility class to make sure that we notify resource that they're promotable
+// before returning from ProcessForOverlays.
+class NotifyPromotionsBeforeReturning {
+ public:
+  NotifyPromotionsBeforeReturning(cc::ResourceProvider* resource_provider,
+                                  cc::OverlayCandidateList* candidates)
+      : resource_provider_(resource_provider), candidates_(candidates) {}
+  ~NotifyPromotionsBeforeReturning() {
+#if defined(OS_ANDROID)
+    resource_provider_->SendPromotionHints(candidates_->promotable_resources_);
+#endif
+  }
+
+ private:
+  cc::ResourceProvider* resource_provider_;
+  cc::OverlayCandidateList* candidates_;
+
+  DISALLOW_COPY_AND_ASSIGN(NotifyPromotionsBeforeReturning);
+};
+
+}  // namespace
+
 namespace cc {
 
 OverlayProcessor::OverlayProcessor(OutputSurface* surface) : surface_(surface) {
@@ -62,6 +87,13 @@ void OverlayProcessor::ProcessForOverlays(ResourceProvider* resource_provider,
                                           OverlayCandidateList* candidates,
                                           CALayerOverlayList* ca_layer_overlays,
                                           gfx::Rect* damage_rect) {
+  // Be sure to send out notifications, regardless of whether we get to
+  // processing for overlays or not.  If we don't, then we should notify that
+  // they are not promotable.
+  // TODO(liberato): should we only notify 'yes' instances, and make the
+  // glimage infer the 'no' instances?  that seems flaky, though.
+  NotifyPromotionsBeforeReturning notify(resource_provider, candidates);
+
   // If we have any copy requests, we can't remove any quads for overlays or
   // CALayers because the framebuffer would be missing the removed quads'
   // contents.