Defer compositor context creation to the thread.

cc/test/test_context_provider.h

Index: cc/test/test_context_provider.h
diff --git a/cc/test/test_context_provider.h b/cc/test/test_context_provider.h
index f294eb7ecd5ba42c7dfbda03498eb3b42026f0dc..73e056003445c680d657ffcfed45ccca7b1296d3 100644
--- a/cc/test/test_context_provider.h
+++ b/cc/test/test_context_provider.h
@@ -30,14 +30,30 @@ class TestContextProvider : public ContextProvider {
       CreateCallback;
 
   static scoped_refptr<TestContextProvider> Create();
-  // Creates a worker context provider that can be used on any thread. This is
-  // equivalent to: Create(); BindToCurrentThread().
-  static scoped_refptr<TestContextProvider> CreateWorker();
   static scoped_refptr<TestContextProvider> Create(
       std::unique_ptr<TestWebGraphicsContext3D> context);
 
-  bool BindToCurrentThread() override;
-  void DetachFromThread() override;
+  class DeferredCreate : public ContextProvider::DeferredCreate {
+   public:
+    DeferredCreate();
+    explicit DeferredCreate(std::unique_ptr<TestWebGraphicsContext3D> context);
+    ~DeferredCreate();
+    scoped_refptr<ContextProvider> CreateContext() override;
+
+    // If true, CreateContext will return null, simulating failure to make the
+    // context.
+    bool fail_create = false;
+    // If set, this TestWebGraphicsContext3D will back the context provider.
+    std::unique_ptr<TestWebGraphicsContext3D> webcontext;
+    // Set on the new context unless a |webcontext| is specified, since it also
+    // contains capabilities.
+    gpu::Capabilities capabilities;
+
+    // Set to non-null to have CreateContext give a pointer to the
+    // TestContextProvider it makes.
+    TestContextProvider** created_context = nullptr;
+  };
+
   gpu::Capabilities ContextCapabilities() override;
   gpu::gles2::GLES2Interface* ContextGL() override;
   gpu::ContextSupport* ContextSupport() override;
@@ -46,6 +62,7 @@ class TestContextProvider : public ContextProvider {
   base::Lock* GetLock() override;
   void DeleteCachedResources() override;
   void SetLostContextCallback(const LostContextCallback& cb) override;
+  void DetachFromThread() override;
 
   TestWebGraphicsContext3D* TestContext3d();
 
@@ -53,6 +70,7 @@ class TestContextProvider : public ContextProvider {
   // before the context is bound to a thread. This is needed to set up
   // state on the test context before binding. Don't call
   // InitializeOnCurrentThread on the context returned from this method.
+  // TODO(danakj): Delete me.
   TestWebGraphicsContext3D* UnboundTestContext3d();
 
   TestContextSupport* support() { return &support_; }
@@ -69,10 +87,8 @@ class TestContextProvider : public ContextProvider {
 
   std::unique_ptr<TestWebGraphicsContext3D> context3d_;
   std::unique_ptr<TestGLES2Interface> context_gl_;
-  bool bound_;
 
-  base::ThreadChecker main_thread_checker_;
-  base::ThreadChecker context_thread_checker_;
+  base::ThreadChecker thread_checker_;
 
   base::Lock context_lock_;