PPAPI: Blocking callbacks shouldn't need a target_loop_

ppapi/shared_impl/tracked_callback.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/shared_impl/tracked_callback.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 147 matching lines @@
   if (completed()) {
     NOTREACHED();
     return;
   }
   if (result == PP_ERROR_ABORTED)
     aborted_ = true;
   // We might abort when there's already a scheduled callback, but callers
   // should never try to PostRun more than once otherwise.
   DCHECK(result == PP_ERROR_ABORTED || !is_scheduled_);
 
-  base::Closure callback_closure(
-      RunWhileLocked(base::Bind(&TrackedCallback::Run, this, result)));
-  if (!target_loop_.get()) {
-    // We must be running in-process and on the main thread (the Enter
-    // classes protect against having a null target_loop_ otherwise).
-    DCHECK(IsMainThread());
-    DCHECK(PpapiGlobals::Get()->IsHostGlobals());
-    base::MessageLoop::current()->PostTask(FROM_HERE, callback_closure);
+  if (is_blocking()) {
+    // We might not have a MessageLoop to post to, so we must call Run()
+    // directly. Since we don't want to attempt to re-acquire the lock, we
+    // don't use the locking closure.

[bbudge, 2013/09/04 22:52:16]

Second part of comment needs tweaking. Maybe s/use the/run a

+    Run(result);
   } else {
-    target_loop_->PostClosure(FROM_HERE, callback_closure, 0);
+    base::Closure callback_closure(
+        RunWhileLocked(base::Bind(&TrackedCallback::Run, this, result)));
+    if (target_loop_) {

[bbudge, 2013/09/04 22:50:36]

Do we have a conversion operator now? Should we start using it elsewhere?

+      target_loop_->PostClosure(FROM_HERE, callback_closure, 0);
+    } else {
+      // We must be running in-process and on the main thread (the Enter
+      // classes protect against having a null target_loop_ otherwise).
+      DCHECK(IsMainThread());
+      DCHECK(PpapiGlobals::Get()->IsHostGlobals());
+      base::MessageLoop::current()->PostTask(FROM_HERE, callback_closure);
+    }
   }
   is_scheduled_ = true;
 }
 
 void TrackedCallback::set_completion_task(
     const CompletionTask& completion_task) {
   DCHECK(completion_task_.is_null());
   completion_task_ = completion_task;
 }
 
@@ skipping 44 matching lines @@
   // until we're done.
   scoped_refptr<TrackedCallback> thiz = this;
   completed_ = true;
   // We may not have a valid resource, in which case we're not in the tracker.
   if (resource_id_)
     tracker_->Remove(thiz);
   tracker_ = NULL;
 }
 
 }  // namespace ppapi