cc: Change required_for_activation bookkeeping.

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 94c3d201639d0dd90a29545ba18ca067f43edd8a..a62b5dfe94e1ba52cb82fa30cd1f4dccb6a86b27 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -56,7 +56,9 @@ PictureLayerImpl::PictureLayerImpl(LayerTreeImpl* tree_impl, int id)
       should_update_tile_priorities_(false),
       should_use_low_res_tiling_(tree_impl->settings().create_low_res_tiling),
       use_gpu_rasterization_(false),
-      layer_needs_to_register_itself_(true) {}
+      layer_needs_to_register_itself_(true),
+      unitialized_tiles_required_for_activation_count_(0u) {
+}
 
 PictureLayerImpl::~PictureLayerImpl() {
   if (!layer_needs_to_register_itself_)
@@ -395,6 +397,7 @@ void PictureLayerImpl::UpdateTilePriorities() {
                                  contents_scale_x(),
                                  current_frame_time_in_seconds);
 
+  unitialized_tiles_required_for_activation_count_ = 0u;
   if (layer_tree_impl()->IsPendingTree())
     MarkVisibleResourcesAsRequired();
 
@@ -402,6 +405,18 @@ void PictureLayerImpl::UpdateTilePriorities() {
   layer_tree_impl()->DidModifyTilePriorities();
 }
 
+void PictureLayerImpl::NotifyTileInitialized(const Tile* tile) {
+  if (layer_tree_impl()->IsActiveTree()) {
+    DCHECK_EQ(0u, unitialized_tiles_required_for_activation_count_);
+    return;
+  }
+
+  if (tile->required_for_activation()) {
+    DCHECK_GT(unitialized_tiles_required_for_activation_count_, 0u);
+    --unitialized_tiles_required_for_activation_count_;
+  }
+}
+
 void PictureLayerImpl::DidBecomeActive() {
   LayerImpl::DidBecomeActive();
   tilings_->DidBecomeActive();
@@ -726,7 +741,7 @@ ResourceProvider::ResourceId PictureLayerImpl::ContentsResourceId() const {
   return tile_version.get_resource_id();
 }
 
-void PictureLayerImpl::MarkVisibleResourcesAsRequired() const {
+void PictureLayerImpl::MarkVisibleResourcesAsRequired() {
   DCHECK(layer_tree_impl()->IsPendingTree());
   DCHECK(!layer_tree_impl()->needs_update_draw_properties());
   DCHECK(ideal_contents_scale_);
@@ -834,7 +849,7 @@ bool PictureLayerImpl::MarkVisibleTilesAsRequired(
     const PictureLayerTiling* optional_twin_tiling,
     float contents_scale,
     const gfx::Rect& rect,
-    const Region& missing_region) const {
+    const Region& missing_region) {
   bool twin_had_missing_tile = false;
   for (PictureLayerTiling::CoverageIterator iter(tiling,
                                                  contents_scale,
@@ -861,8 +876,10 @@ bool PictureLayerImpl::MarkVisibleTilesAsRequired(
         continue;
       }
     }
-
+    DCHECK(!tile->required_for_activation());
     tile->MarkRequiredForActivation();
+    if (!tile->IsReadyToDraw())
+      ++unitialized_tiles_required_for_activation_count_;
   }
   return twin_had_missing_tile;
 }