Delay activation/draw on GPU tile work completion

cc/tiles/tile_draw_info.h

Index: cc/tiles/tile_draw_info.h
diff --git a/cc/tiles/tile_draw_info.h b/cc/tiles/tile_draw_info.h
index a51d27b9916df2e3b6aa73c0983f9f95f2005d5d..a60837a60a1e0c2f0676daa57ed9babfb093d9c1 100644
--- a/cc/tiles/tile_draw_info.h
+++ b/cc/tiles/tile_draw_info.h
@@ -27,7 +27,7 @@ class CC_EXPORT TileDrawInfo {
   bool IsReadyToDraw() const {
     switch (mode_) {
       case RESOURCE_MODE:
-        return !!resource_;
+        return is_resource_ready_to_draw_;
       case SOLID_COLOR_MODE:
       case OOM_MODE:
         return true;
@@ -81,7 +81,6 @@ class CC_EXPORT TileDrawInfo {
 
   void AsValueInto(base::trace_event::TracedValue* state) const;
 
-  void set_was_ever_ready_to_draw() { was_ever_ready_to_draw_ = true; }
   void set_was_ever_used_to_draw() { was_ever_used_to_draw_ = true; }
   void set_was_a_prepaint_tile() { was_a_prepaint_tile_ = true; }
 
@@ -89,19 +88,30 @@ class CC_EXPORT TileDrawInfo {
   friend class Tile;
   friend class TileManager;
 
-  void set_use_resource() { mode_ = RESOURCE_MODE; }
+  void set_resource(Resource* resource) {
+    mode_ = RESOURCE_MODE;
+    is_resource_ready_to_draw_ = false;
+    resource_ = resource;
+  }
+
+  void set_resource_ready_for_draw() {
+    is_resource_ready_to_draw_ = true;
+    was_ever_ready_to_draw_ = true;
+  }
 
   void set_solid_color(const SkColor& color) {
     mode_ = SOLID_COLOR_MODE;
     solid_color_ = color;
+    was_ever_ready_to_draw_ = true;
   }
 
   void set_oom() { mode_ = OOM_MODE; }
 
-  Mode mode_;
-  SkColor solid_color_;
-  Resource* resource_;
-  bool contents_swizzled_;
+  Mode mode_ = RESOURCE_MODE;
+  SkColor solid_color_ = SK_ColorWHITE;
+  Resource* resource_ = nullptr;
+  bool contents_swizzled_ = false;
+  bool is_resource_ready_to_draw_ = false;
 
   // Used for gathering UMA stats.
   bool was_ever_ready_to_draw_ : 1;