Provide TaskRunner to ContextCacheController

cc/output/context_cache_controller.h

Index: cc/output/context_cache_controller.h
diff --git a/cc/output/context_cache_controller.h b/cc/output/context_cache_controller.h
index fb1ab9f4efb59a3273b158d6ac5c31dd555b6d66..03f7e2cd74f9117e11cb95ac6db4a747199301f7 100644
--- a/cc/output/context_cache_controller.h
+++ b/cc/output/context_cache_controller.h
@@ -9,10 +9,15 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "cc/base/cc_export.h"
 
 class GrContext;
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace gpu {
 class ContextSupport;
 }
@@ -41,7 +46,9 @@ class CC_EXPORT ContextCacheController {
     bool released_ = false;
   };
 
-  explicit ContextCacheController(gpu::ContextSupport* context_support);
+  ContextCacheController(
+      gpu::ContextSupport* context_support,
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner);
   virtual ~ContextCacheController();
 
   void SetGrContext(GrContext* gr_context);
@@ -64,6 +71,7 @@ class CC_EXPORT ContextCacheController {
 
  private:
   gpu::ContextSupport* context_support_;
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   GrContext* gr_context_ = nullptr;
 
   uint32_t num_clients_visible_ = 0;