Add preliminary support for hw-accelerated tile 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 626b587b3145261faa06cd9f653c7edd449e7dcb..bfa7433fcd6a7338a28f4deebf71ca5d2e2d2fae 100644
--- a/cc/test/test_context_provider.cc
+++ b/cc/test/test_context_provider.cc
@@ -12,6 +12,8 @@
 #include "base/logging.h"
 #include "cc/test/test_gles2_interface.h"
 #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"
 
 namespace cc {
 
@@ -115,8 +117,12 @@ class GrContext* TestContextProvider::GrContext() {
   DCHECK(bound_);
   DCHECK(context_thread_checker_.CalledOnValidThread());
 
-  // TODO(danakj): Make a test GrContext that works with a test Context3d.
-  return NULL;
+  if (!gr_context_) {
+    gr_context_ = skia::AdoptRef(GrContext::Create(
+        kOpenGL_GrBackend,
+        reinterpret_cast<GrBackendContext>(GrGLCreateNullInterface())));
+  }
+  return gr_context_.get();
 }
 
 void TestContextProvider::MakeGrContextCurrent() {}