[cc] Evict UIResources when the renderer is not visible

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 0d4fbf9fd0806d37a567c2559c45470da83ad913..9939f34555e72016b401e72601db1ea79914eeef 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -33,6 +33,7 @@ LayerTreeImpl::LayerTreeImpl(LayerTreeHostImpl* layer_tree_host_impl)
       min_page_scale_factor_(0),
       max_page_scale_factor_(0),
       scrolling_layer_id_from_previous_tree_(0),
+      ui_resource_eviction_count_recreated_(0),
       contents_textures_purged_(false),
       viewport_size_invalid_(false),
       needs_update_draw_properties_(true),
@@ -126,6 +127,9 @@ void LayerTreeImpl::PushPropertiesTo(LayerTreeImpl* target_tree) {
   else
     target_tree->ResetContentsTexturesPurged();
 
+  target_tree->SetUIResourceEvictionCountRecreated(
+      ui_resource_eviction_count_recreated_);
+
   if (ViewportSizeInvalid())
     target_tree->SetViewportSizeInvalid();
   else
@@ -383,6 +387,21 @@ void LayerTreeImpl::DidBecomeActive() {
   FindRootScrollLayer();
 }
 
+void LayerTreeImpl::SetUIResourceEvictionCountRecreated(
+    uint64 ui_resource_eviction_count_recreated) {
+  if (ui_resource_eviction_count_recreated ==
+      ui_resource_eviction_count_recreated_)
+    return;
+
+  ui_resource_eviction_count_recreated_ = ui_resource_eviction_count_recreated;
+  layer_tree_host_impl_->OnCanDrawStateChangedForTree();
+}
+
+bool LayerTreeImpl::UIResourcesEvictedHaveNotBeenRecreated() const {
+  return layer_tree_host_impl_->ui_resource_eviction_count() !=
+      ui_resource_eviction_count_recreated_;
+}
+
 bool LayerTreeImpl::ContentsTexturesPurged() const {
   return contents_textures_purged_;
 }
@@ -624,6 +643,9 @@ void LayerTreeImpl::ProcessUIResourceRequestQueue() {
       case UIResourceRequest::UIResourceDelete:
         layer_tree_host_impl_->DeleteUIResource(req.id);
         break;
+      case UIResourceRequest::UIResourceEvictionRecreated:
+        SetUIResourceEvictionCountRecreated(req.eviction_count_recreated);
+        break;
       case UIResourceRequest::UIResourceInvalidRequest:
         NOTREACHED();
         break;