Move in-GPU mojo:media app to new thread

content/public/common/mojo_application_info.h

 // Copyright 2015 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.
 
 #ifndef CONTENT_PUBLIC_COMMON_MOJO_APPLICATION_INFO_H_
 #define CONTENT_PUBLIC_COMMON_MOJO_APPLICATION_INFO_H_
 
 #include <memory>
 
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
 #include "services/shell/public/cpp/shell_client.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace content {
 
+// MojoApplicationInfo provides details necessary to construct and bind new
+// instances of embedded Mojo applications.
 struct CONTENT_EXPORT MojoApplicationInfo {
   using ApplicationFactory = base::Callback<std::unique_ptr<shell::ShellClient>(
       const base::Closure& quit_closure)>;
 
   MojoApplicationInfo();
   MojoApplicationInfo(const MojoApplicationInfo& other);
   ~MojoApplicationInfo();
 
+  // A factory function which will be called to produce a new ShellClient
+  // instance for this app whenever one is needed.
   ApplicationFactory application_factory;
+
+  // The task runner on which to construct and bind new ShellClient instances
+  // for this app. If null, behavior depends on the value of |use_own_thread|
+  // below.
   scoped_refptr<base::SingleThreadTaskRunner> application_task_runner;
+
+  // If |application_task_runner| is null, setting this to |true| will give
+  // each instance of this app its own thread to run on. Setting this to |false|
+  // (the default) will instead run the app on the main thread's task runner.
+  //
+  // If |application_task_runner| is not null, this value is ignored.
+  bool use_own_thread = false;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_COMMON_MOJO_APPLICATION_INFO_H_