[content] Expose renderer scheduler task queues in content::RenderThread.

content/public/test/mock_render_thread.cc

Index: content/public/test/mock_render_thread.cc
diff --git a/content/public/test/mock_render_thread.cc b/content/public/test/mock_render_thread.cc
index 4c9afbb0a9499a230a220f82dfabed1439bb6000..2ab1d2ae384d57dd7af01ed930f9f798eea09911 100644
--- a/content/public/test/mock_render_thread.cc
+++ b/content/public/test/mock_render_thread.cc
@@ -249,6 +249,16 @@ int32_t MockRenderThread::GetClientId() {
   return 1;
 }
 
+scoped_refptr<base::SingleThreadTaskRunner>
+MockRenderThread::GetTimerTaskRunner() {
+  return base::ThreadTaskRunnerHandle::Get();
+}
+
+scoped_refptr<base::SingleThreadTaskRunner>
+MockRenderThread::GetLoadingTaskRunner() {
+  return base::ThreadTaskRunnerHandle::Get();
+}
+
 #if defined(OS_WIN)
 void MockRenderThread::PreCacheFont(const LOGFONT& log_font) {
 }