[cc] Evict UIResources when the renderer is not visible

cc/trees/layer_tree_host_impl.h

Index: cc/trees/layer_tree_host_impl.h
diff --git a/cc/trees/layer_tree_host_impl.h b/cc/trees/layer_tree_host_impl.h
index 55ccab68a6b0cdc647602a703bbbc8923a820300..f420fb86bfb201699fe77fe1e213efc690910bd2 100644
--- a/cc/trees/layer_tree_host_impl.h
+++ b/cc/trees/layer_tree_host_impl.h
@@ -342,6 +342,10 @@ class CC_EXPORT LayerTreeHostImpl
     return animation_registrar_.get();
   }
 
+  uint64 ui_resource_eviction_count() const {
+    return ui_resource_eviction_count_;
+  }
+
   void SetDebugState(const LayerTreeDebugState& new_debug_state);
   const LayerTreeDebugState& debug_state() const { return debug_state_; }
 
@@ -599,6 +603,13 @@ class CC_EXPORT LayerTreeHostImpl
 
   bool need_to_update_visible_tiles_before_draw_;
 
+  // The number of times that UI resources have been evicted since creation.
+  // This is passed to LayerTreeHost at frame creation. If the LayerTreeHost
+  // has not recreated its resources for this eviction count, it will recreate
+  // all resources and pass this counter back through the UI resource update
+  // queue.
+  uint64 ui_resource_eviction_count_;
+
   // Optional callback to notify of new tree activations.
   base::Closure tree_activation_callback_;