Forward input tasks to the Blink scheduler

cc/trees/proxy.cc

Index: cc/trees/proxy.cc
diff --git a/cc/trees/proxy.cc b/cc/trees/proxy.cc
index a8f7b26fb04a150c7ad2f58c31553a59dc625997..22ecdfae00fc08b62cbac9859aa75cc30b38e6d9 100644
--- a/cc/trees/proxy.cc
+++ b/cc/trees/proxy.cc
@@ -9,7 +9,7 @@
 
 namespace cc {
 
-base::SingleThreadTaskRunner* Proxy::MainThreadTaskRunner() const {
+MainThreadTaskRunner* Proxy::MainThreadTaskRunner() const {
   return main_task_runner_.get();
 }
 
@@ -66,11 +66,14 @@ void Proxy::SetMainThreadBlocked(bool is_main_thread_blocked) {
 }
 #endif
 
-Proxy::Proxy(scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner)
-    : main_task_runner_(base::MessageLoopProxy::current()),
+Proxy::Proxy(
+   scoped_refptr<cc::MainThreadTaskRunner> main_task_runner,
+   scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner)
 #if !DCHECK_IS_ON
+    : main_task_runner_(main_task_runner),
       impl_task_runner_(impl_task_runner) {
 #else
+    : main_task_runner_(main_task_runner),
       impl_task_runner_(impl_task_runner),
       main_thread_id_(base::PlatformThread::CurrentId()),
       impl_thread_is_overridden_(false),