UI resource are evicted when LTH is set to not visible.

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 73033a19b4866e75645d5cf21735c3bcd0ab92b8..9ac59cf3548eb0d4a21b24ca4050f41a5c363c83 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -4469,6 +4469,139 @@ class LayerTreeHostTestAbortEvictedTextures : public LayerTreeHostTest {
 // Commits can only be aborted when using the thread proxy.
 MULTI_THREAD_TEST_F(LayerTreeHostTestAbortEvictedTextures);
 
+class TestWebGraphicsContext3DWithTextureCounts
+    : public TestWebGraphicsContext3D {
+ public:
+  static scoped_ptr<TestWebGraphicsContext3DWithTextureCounts> Create() {
+    return make_scoped_ptr(new TestWebGraphicsContext3DWithTextureCounts());
+  }
+
+  virtual ~TestWebGraphicsContext3DWithTextureCounts() {}
+
+  virtual WebKit::WebGLId createTexture() OVERRIDE {
+    ++num_create_texture_calls_;
+    return TestWebGraphicsContext3D::createTexture();
+  }
+
+  virtual void deleteTexture(WebKit::WebGLId texture_id) OVERRIDE {
+    ++num_delete_texture_calls_;
+    TestWebGraphicsContext3D::deleteTexture(texture_id);
+  }
+
+  int num_create_texture_calls_;
+  int num_delete_texture_calls_;
+
+ private:
+  TestWebGraphicsContext3DWithTextureCounts()
+      : TestWebGraphicsContext3D(),
+        num_create_texture_calls_(0),
+        num_delete_texture_calls_(0) {}
+};
+
+// UI resources should be evicted when visibility is set to false and recreated
+// when visibility is set to true.
+class LayerTreeHostEvictUIResourceTest : public LayerTreeHostTest {
+ public:
+  LayerTreeHostEvictUIResourceTest()
+      : LayerTreeHostTest(), num_commits_(0), context3d_(NULL) {}
+
+  virtual scoped_ptr<TestWebGraphicsContext3DWithTextureCounts>
+  CreateContext3d() {
+    return TestWebGraphicsContext3DWithTextureCounts::Create();
+  }
+
+  virtual scoped_ptr<OutputSurface> CreateOutputSurface(
+      bool fallback) OVERRIDE {
+    scoped_ptr<TestWebGraphicsContext3DWithTextureCounts> context3d =
+        CreateContext3d();
+    context3d_ = context3d.get();
+    return FakeOutputSurface::Create3d(
+        context3d.PassAs<TestWebGraphicsContext3D>()).PassAs<OutputSurface>();
+  }
+
+  virtual void BeginTest() OVERRIDE { PostSetNeedsCommitToMainThread(); }
+
+  virtual void SetupTree() OVERRIDE {
+    root_ = Layer::Create();
+    bool paint_scrollbar = true;
+    bool has_thumb = false;
+    scrollbar_layer_ = FakePaintedScrollbarLayer::Create(
+        paint_scrollbar, has_thumb, root_->id());
+
+    root_->AddChild(scrollbar_layer_);
+    layer_tree_host()->SetRootLayer(root_);
+    LayerTreeHostTest::SetupTree();
+  }
+
+  virtual void DidCommit() OVERRIDE {
+    int frame = num_commits_;
+    scoped_ptr<base::AutoReset<bool> > ignore;
+    switch (frame) {
+      case 1:
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 2:
+        PostSetVisibleToMainThread(false);
+        PostSetNeedsRedrawToMainThread();
+        PostSetVisibleToMainThread(true);
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 3:
+        PostSetNeedsCommitToMainThread();
+        break;
+      case 4:
+        EndTest();
+        break;
+    }
+  }
+
+  virtual void PerformTest(LayerTreeHostImpl* impl) {
+    int frame = num_commits_;
+    switch (frame) {
+      case 1:
+        // Expect one texture has been created.  None has been deleted.
+        EXPECT_EQ(context3d_->num_create_texture_calls_, 1);
+        EXPECT_EQ(context3d_->num_delete_texture_calls_, 0);
+        break;
+      case 2:
+        // Expect two textures has been created.  One has been deleted.
+        EXPECT_EQ(context3d_->num_create_texture_calls_, 2);
+        EXPECT_EQ(context3d_->num_delete_texture_calls_, 1);
+        break;
+      case 3:
+        // Visibility has been changed once.  So resource was evicted in LTHI
+        // and recreated in LTH.  Expect four textures has been created.  Three
+        // has been deleted.
+        EXPECT_EQ(context3d_->num_create_texture_calls_, 4);
+        EXPECT_EQ(context3d_->num_delete_texture_calls_, 3);
+        break;
+      default:
+        break;
+    }
+  }
+
+  virtual void CommitCompleteOnThread(LayerTreeHostImpl* impl) OVERRIDE {
+    ++num_commits_;
+    if (!layer_tree_host()->settings().impl_side_painting)
+      PerformTest(impl);
+  }
+
+  virtual void DidActivateTreeOnThread(LayerTreeHostImpl* impl) OVERRIDE {
+    if (layer_tree_host()->settings().impl_side_painting)
+      PerformTest(impl);
+  }
+
+  virtual void AfterTest() OVERRIDE {}
+
+ protected:
+  scoped_refptr<Layer> root_;
+  scoped_refptr<FakePaintedScrollbarLayer> scrollbar_layer_;
+  int num_commits_;
+  TestWebGraphicsContext3DWithTextureCounts* context3d_;
+};
+
+SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostEvictUIResourceTest);
+
 }  // namespace
 
 }  // namespace cc