Prevent recreation of UI resource holder when created with resource ID

cc/layers/ui_resource_layer.cc

Index: cc/layers/ui_resource_layer.cc
diff --git a/cc/layers/ui_resource_layer.cc b/cc/layers/ui_resource_layer.cc
index 944cf7d54844c7016feb32eacfc401fb590146ab..2291ece892b4497b1ec6c044be21b3d9b703eed7 100644
--- a/cc/layers/ui_resource_layer.cc
+++ b/cc/layers/ui_resource_layer.cc
@@ -25,6 +25,8 @@ class ScopedUIResourceHolder : public UIResourceLayer::UIResourceHolder {
   }
   UIResourceId id() override { return resource_->id(); }
 
+  bool NeedsRecreation() override { return false; }
+
  private:
   ScopedUIResourceHolder(LayerTreeHost* host, const SkBitmap& skbitmap) {
     resource_ = ScopedUIResource::Create(host, UIResourceBitmap(skbitmap));
@@ -35,16 +37,21 @@ class ScopedUIResourceHolder : public UIResourceLayer::UIResourceHolder {
 
 class SharedUIResourceHolder : public UIResourceLayer::UIResourceHolder {
  public:
-  static scoped_ptr<SharedUIResourceHolder> Create(UIResourceId id) {
-    return make_scoped_ptr(new SharedUIResourceHolder(id));
+  static scoped_ptr<SharedUIResourceHolder> Create(UIResourceId id,
+                                                   bool is_persistent) {
+    return make_scoped_ptr(new SharedUIResourceHolder(id, is_persistent));
   }
 
   UIResourceId id() override { return id_; }
 
+  bool NeedsRecreation() override { return !is_persistent_; }
+
  private:
-  explicit SharedUIResourceHolder(UIResourceId id) : id_(id) {}
+  SharedUIResourceHolder(UIResourceId id, bool is_persistent)
+      : id_(id), is_persistent_(is_persistent) {}
 
   UIResourceId id_;
+  bool is_persistent_;
 };
 
 }  // anonymous namespace
@@ -112,10 +119,11 @@ void UIResourceLayer::SetLayerTreeHost(LayerTreeHost* host) {
 }
 
 void UIResourceLayer::RecreateUIResourceHolder() {
-  ui_resource_holder_ = nullptr;
   if (layer_tree_host() && !bitmap_.empty()) {
     ui_resource_holder_ =
         ScopedUIResourceHolder::Create(layer_tree_host(), bitmap_);
+  } else if (ui_resource_holder_ && !ui_resource_holder_->NeedsRecreation()) {
+    ui_resource_holder_ = nullptr;
   }
   UpdateDrawsContent(HasDrawableContent());
 }
@@ -128,11 +136,21 @@ void UIResourceLayer::SetBitmap(const SkBitmap& skbitmap) {
 }
 
 void UIResourceLayer::SetUIResourceId(UIResourceId resource_id) {
+  SetUIResourceIdInternal(resource_id, false);
+}
+
+void UIResourceLayer::SetPersistentUIResourceId(UIResourceId resource_id) {
+  SetUIResourceIdInternal(resource_id, true);
+}
+
+void UIResourceLayer::SetUIResourceIdInternal(UIResourceId resource_id,
+                                              bool is_persistent) {
   if (ui_resource_holder_ && ui_resource_holder_->id() == resource_id)
     return;
 
   if (resource_id)
-    ui_resource_holder_ = SharedUIResourceHolder::Create(resource_id);
+    ui_resource_holder_ =
+        SharedUIResourceHolder::Create(resource_id, is_persistent);
   else
     ui_resource_holder_ = nullptr;