cc: Add threaded GPU rasterization.

cc/test/test_context_provider.cc

Index: cc/test/test_context_provider.cc
diff --git a/cc/test/test_context_provider.cc b/cc/test/test_context_provider.cc
index 4c24fe1efebaaa4bcdc376212aa606f4345270fb..2f3a6381afeb0ca3e56cdc379a1e7c8bb8a48a01 100644
--- a/cc/test/test_context_provider.cc
+++ b/cc/test/test_context_provider.cc
@@ -14,6 +14,7 @@
 #include "cc/test/test_web_graphics_context_3d.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 #include "third_party/skia/include/gpu/gl/GrGLInterface.h"
+#include "third_party/skia/include/gpu/gl/SkNullGLContext.h"
 
 namespace cc {
 
@@ -69,6 +70,10 @@ bool TestContextProvider::BindToCurrentThread() {
   return true;
 }
 
+void TestContextProvider::DetachFromThread() {
+  context_thread_checker_.DetachFromThread();
+}
+
 ContextProvider::Capabilities TestContextProvider::ContextCapabilities() {
   DCHECK(bound_);
   DCHECK(context_thread_checker_.CalledOnValidThread());
@@ -95,11 +100,11 @@ class GrContext* TestContextProvider::GrContext() {
   if (gr_context_)
     return gr_context_.get();
 
-  skia::RefPtr<const GrGLInterface> null_interface =
-      skia::AdoptRef(GrGLCreateNullInterface());
-  gr_context_ = skia::AdoptRef(GrContext::Create(
-      kOpenGL_GrBackend,
-      reinterpret_cast<GrBackendContext>(null_interface.get())));
+  gl_context_ = skia::AdoptRef(SkNullGLContext::Create(kNone_GrGLStandard));
+  gl_context_->makeCurrent();
+  gr_context_ = skia::AdoptRef(
+      GrContext::Create(kOpenGL_GrBackend,
+                        reinterpret_cast<GrBackendContext>(gl_context_->gl())));
   return gr_context_.get();
 }