Never lock the Pepper proxy lock on the IO thread

ppapi/shared_impl/tracked_callback.cc

Index: ppapi/shared_impl/tracked_callback.cc
diff --git a/ppapi/shared_impl/tracked_callback.cc b/ppapi/shared_impl/tracked_callback.cc
index 8e353463c3c848c198e591157fbb4a9d1b71c364..103d58fedccb058c4a9958e61744cf26d85b61e9 100644
--- a/ppapi/shared_impl/tracked_callback.cc
+++ b/ppapi/shared_impl/tracked_callback.cc
@@ -37,12 +37,6 @@ int32_t RunCompletionTask(TrackedCallback::CompletionTask completion_task,
   return result;
 }
 
-void AcquireProxyLockAndRun(const base::Closure& closure) {
-  ProxyAutoLock acquire;
-  closure.Run();
-}
-
-
 }  // namespace
 
 // TrackedCallback -------------------------------------------------------------
@@ -252,14 +246,8 @@ void TrackedCallback::PostRunWithLock(int32_t result) {
     // directly.
     SignalBlockingCallback(result);
   } else {
-    // Note we can't use "RunWhileLocked" from proxy_lock.h, because it requires
-    // that the ProxyLock is held (to protect Resource and Var ref-counting).
-    // Here, we must not acquire the ProxyLock, because we may be on the IO
-    // thread. But we're not passing any parameters that would require
-    // the ProxyLock (such as Var or Resource).
     base::Closure callback_closure(
-        base::Bind(&ppapi::AcquireProxyLockAndRun,
-            base::Bind(&TrackedCallback::Run, this, result)));
+        RunWhileLocked(base::Bind(&TrackedCallback::Run, this, result)));

[raymes, 2015/03/25 01:43:59]

I don't really understand this change but maybe bbudge would be better to
comment on it since he looked at the TrackedCallback stuff more?

[dmichael (off chromium), 2015/03/25 17:35:04]

That CL hasn't landed yet, and you're right...  this change really belongs
there, so I moved it out of this CL.

     if (target_loop_) {
       target_loop_->PostClosure(FROM_HERE, callback_closure, 0);
     } else {