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..cb5794ed0e5b1f598e69a19e62253d3c43d0946d 100644
--- a/cc/test/test_context_provider.h
+++ b/cc/test/test_context_provider.h
@@ -30,14 +30,33 @@ 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 Factory : public ContextProvider::Factory {
+   public:
+    // Creates a context provider with default capabilities.
+    Factory();
+    // Creates a context provider wrapping the given TestWebGraphicsContext3D.
+    explicit Factory(std::unique_ptr<TestWebGraphicsContext3D> context);
+    // Creates a context provider with the given capabilities.
+    explicit Factory(const gpu::Capabilities& capabilities);
+    // Fails to create a context provider, simulating loss of the gpu channel or
+    // other such error conditions.
+    enum FailCreate { kFailCreate = 1 };
+    explicit Factory(FailCreate);
+
+    ~Factory();
+    scoped_refptr<ContextProvider> CreateContext() override;
+
+   private:

[danakj, 2016/05/17 23:17:15]

Notably I made these private and added constructors so it's harder to use it
wrong, and you can just write MakeUnique<T> once instead of needing an lvalue to
set stuff on.

+    const bool fail_create_ = false;
+    std::unique_ptr<TestWebGraphicsContext3D> context_;
+    const gpu::Capabilities capabilities_;
+
+    DISALLOW_COPY_AND_ASSIGN(Factory);
+  };
+
   gpu::Capabilities ContextCapabilities() override;
   gpu::gles2::GLES2Interface* ContextGL() override;
   gpu::ContextSupport* ContextSupport() override;
@@ -46,15 +65,9 @@ class TestContextProvider : public ContextProvider {
   base::Lock* GetLock() override;
   void DeleteCachedResources() override;
   void SetLostContextCallback(const LostContextCallback& cb) override;
+  void DetachFromThread() override;
 
   TestWebGraphicsContext3D* TestContext3d();
-
-  // This returns the TestWebGraphicsContext3D but is valid to call
-  // 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.
-  TestWebGraphicsContext3D* UnboundTestContext3d();
-
   TestContextSupport* support() { return &support_; }
 
  protected:
@@ -69,10 +82,8 @@ 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_;