Defer compositor context creation to the thread.

cc/output/renderer_unittest.cc

Index: cc/output/renderer_unittest.cc
diff --git a/cc/output/renderer_unittest.cc b/cc/output/renderer_unittest.cc
index 67d13caf40a7f6af65e2308488ea2268fc4c30d1..a69f5d4feb7dd7f68cf8620ec64a7c2ce17d00b4 100644
--- a/cc/output/renderer_unittest.cc
+++ b/cc/output/renderer_unittest.cc
@@ -18,7 +18,8 @@ namespace {
 
 class TestOutputSurface : public OutputSurface {
  public:
-  explicit TestOutputSurface(scoped_refptr<ContextProvider> context_provider);
+  explicit TestOutputSurface(
+      std::unique_ptr<ContextProvider::DeferredCreate> context_provider_create);
   ~TestOutputSurface() override;
 
   // OutputSurface implementation
@@ -26,8 +27,8 @@ class TestOutputSurface : public OutputSurface {
 };
 
 TestOutputSurface::TestOutputSurface(
-    scoped_refptr<ContextProvider> context_provider)
-    : OutputSurface(std::move(context_provider)) {}
+    std::unique_ptr<ContextProvider::DeferredCreate> context_provider_create)
+    : OutputSurface(std::move(context_provider_create)) {}
 
 TestOutputSurface::~TestOutputSurface() {
 }
@@ -39,9 +40,23 @@ void TestOutputSurface::SwapBuffers(CompositorFrame* frame) {
 
 class MockContextProvider : public TestContextProvider {
  public:
-  explicit MockContextProvider(
-      std::unique_ptr<TestWebGraphicsContext3D> context)
-      : TestContextProvider(std::move(context)) {}
+  MockContextProvider()
+      : TestContextProvider(TestWebGraphicsContext3D::Create()) {}
+
+  class DeferredCreate : public ContextProvider::DeferredCreate {
+   public:
+    explicit DeferredCreate(MockContextProvider** created)
+        : created_(created) {}
+    scoped_refptr<ContextProvider> CreateContext() override {
+      scoped_refptr<MockContextProvider> context(new MockContextProvider);
+      *created_ = context.get();
+      return context;
+    }
+
+   private:
+    MockContextProvider** created_;
+  };
+
   MOCK_METHOD0(DeleteCachedResources, void());
 
  protected:
@@ -78,9 +93,9 @@ template <typename T>
 class RendererTest : public ::testing::Test {
  protected:
   virtual void SetUp() {
-    context_provider_ =
-        new MockContextProvider(TestWebGraphicsContext3D::Create());
-    output_surface_.reset(new TestOutputSurface(context_provider_));
+    output_surface_.reset(new TestOutputSurface(
+        base::MakeUnique<MockContextProvider::DeferredCreate>(
+            &context_provider_)));

[piman, 2016/05/17 03:41:40]

How about still creating the context provider here, pass it to the
MockContextProvider::DeferredCreate which just returns it directly in
CreateContext?

[danakj, 2016/05/17 19:53:33]

That is a pretty good idea. Done.

     output_surface_->BindToClient(&output_surface_client_);
     resource_provider_ =
         FakeResourceProvider::Create(output_surface_.get(), nullptr);
@@ -93,7 +108,7 @@ class RendererTest : public ::testing::Test {
   FakeRendererClient renderer_client_;
   RendererSettings tree_settings_;
   FakeOutputSurfaceClient output_surface_client_;
-  scoped_refptr<MockContextProvider> context_provider_;
+  MockContextProvider* context_provider_;
   std::unique_ptr<OutputSurface> output_surface_;
   std::unique_ptr<ResourceProvider> resource_provider_;
   std::unique_ptr<Renderer> renderer_;
@@ -103,8 +118,7 @@ typedef ::testing::Types<DelegatingRenderer, GLRenderer> RendererTypes;
 TYPED_TEST_CASE(RendererTest, RendererTypes);
 
 TYPED_TEST(RendererTest, ContextPurgedWhenRendererBecomesInvisible) {
-  EXPECT_CALL(*(this->context_provider_.get()), DeleteCachedResources())
-      .Times(1);
+  EXPECT_CALL(*this->context_provider_, DeleteCachedResources()).Times(1);
 
   EXPECT_TRUE(this->renderer_->visible());
   this->renderer_->SetVisible(false);