Keeping track of descendants that draw content instead of recalcualting

cc/trees/layer_tree_host_unittest.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/synchronization/lock.h"
@@ skipping 2958 matching lines @@
     if (persist_needs_push_properties_)
       needs_push_properties_ = true;
   }
 
   virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
       OVERRIDE {
     return PushPropertiesCountingLayerImpl::Create(tree_impl, id()).
         PassAs<LayerImpl>();
   }
 
+  void SetDrawsContent(bool draws_content) {
+    UpdateDrawsContent(draws_content);
+  }
+
   size_t push_properties_count() const { return push_properties_count_; }
   void reset_push_properties_count() { push_properties_count_ = 0; }
 
   void set_persist_needs_push_properties(bool persist) {
     persist_needs_push_properties_ = persist;
   }
 
  private:
   PushPropertiesCountingLayer()
       : push_properties_count_(0), persist_needs_push_properties_(false) {
     SetBounds(gfx::Size(1, 1));
-    SetIsDrawable(true);
   }
   virtual ~PushPropertiesCountingLayer() {}
 
   size_t push_properties_count_;
   bool persist_needs_push_properties_;
 };
 
 class LayerTreeHostTestLayersPushProperties : public LayerTreeHostTest {
  protected:
   virtual void BeginTest() OVERRIDE {
@@ skipping 436 matching lines @@
   }
 
   virtual void AfterTest() OVERRIDE {}
 
   scoped_refptr<Layer> root_;
   scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer_;
 };
 
 MULTI_THREAD_TEST_F(LayerTreeHostTestPropertyChangesDuringUpdateArePushed);
 
+class LayerTreeHostTestSetDrawableCausesCommit : public LayerTreeHostTest {
+ protected:
+  virtual void BeginTest() OVERRIDE { PostSetNeedsCommitToMainThread(); }
+
+  virtual void SetupTree() OVERRIDE {
+    root_ = PushPropertiesCountingLayer::Create();
+    child_ = PushPropertiesCountingLayer::Create();
+    root_->AddChild(child_);
+
+    layer_tree_host()->SetRootLayer(root_);
+    LayerTreeHostTest::SetupTree();
+  }
+
+  virtual void DidCommitAndDrawFrame() OVERRIDE {
+    switch (layer_tree_host()->source_frame_number()) {
+      case 0:
+        break;
+      case 1: {
+        // During update, the ignore_set_needs_commit_ bit is set to true to
+        // avoid causing a second commit to be scheduled. If a property change
+        // is made during this, however, it needs to be pushed in the upcoming
+        // commit.
+        EXPECT_FALSE(root_->needs_push_properties());
+        EXPECT_FALSE(child_->needs_push_properties());
+        EXPECT_EQ(0, root_->NumDescendantsThatDrawContent());
+        root_->reset_push_properties_count();
+        child_->reset_push_properties_count();
+        child_->SetDrawsContent(true);
+        EXPECT_EQ(1, root_->NumDescendantsThatDrawContent());
+        EXPECT_EQ(0u, root_->push_properties_count());
+        EXPECT_EQ(0u, child_->push_properties_count());
+        EXPECT_TRUE(root_->needs_push_properties());
+        EXPECT_TRUE(child_->needs_push_properties());
+        break;
+      }
+      case 2:
+        EXPECT_EQ(1u, root_->push_properties_count());
+        EXPECT_EQ(1u, child_->push_properties_count());
+        EXPECT_FALSE(root_->needs_push_properties());
+        EXPECT_FALSE(child_->needs_push_properties());
+        EndTest();
+        break;
+    }
+  }
+
+  virtual void AfterTest() OVERRIDE {}
+
+  scoped_refptr<PushPropertiesCountingLayer> root_;
+  scoped_refptr<PushPropertiesCountingLayer> child_;
+};
+
+MULTI_THREAD_TEST_F(LayerTreeHostTestSetDrawableCausesCommit);
+
 class LayerTreeHostTestCasePushPropertiesThreeGrandChildren
     : public LayerTreeHostTest {
  protected:
   virtual void BeginTest() OVERRIDE {
     expected_push_properties_root_ = 0;
     expected_push_properties_child_ = 0;
     expected_push_properties_grandchild1_ = 0;
     expected_push_properties_grandchild2_ = 0;
     expected_push_properties_grandchild3_ = 0;
     PostSetNeedsCommitToMainThread();
@@ skipping 1442 matching lines @@
   const gfx::Size bounds_;
   FakeContentLayerClient client_;
   scoped_refptr<ContentLayerWithUpdateTracking> content_layer_;
   scoped_refptr<FakePictureLayer> picture_layer_;
   Layer* child_layer_;
 };
 
 MULTI_THREAD_TEST_F(LayerTreeHostTestContinuousPainting);
 
 }  // namespace cc