Make the GPU process use an X11 event loop

base/message_loop/message_loop.h

 // Copyright 2013 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 BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 #define BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_
 
 #include <queue>
 #include <string>
 
@@ skipping 87 matching lines @@
   // A MessageLoop has a particular type, which indicates the set of
   // asynchronous events it may process in addition to tasks and timers.
   //
   // TYPE_DEFAULT
   //   This type of ML only supports tasks and timers.
   //
   // TYPE_UI
   //   This type of ML also supports native UI events (e.g., Windows messages).
   //   See also MessageLoopForUI.
   //
+  // TYPE_UI_GPU
+  //   This type of ML also supports native UI events for use in the GPU
+  //   process. On Linux this will always be an X11 ML (as compared with the
+  //   sometimes-GTK ML in the browser).
+  //
   // TYPE_IO
   //   This type of ML also supports asynchronous IO.  See also
   //   MessageLoopForIO.
   //
   // TYPE_JAVA
   //   This type of ML is backed by a Java message handler which is responsible
   //   for running the tasks added to the ML. This is only for use on Android.
   //   TYPE_JAVA behaves in essence like TYPE_UI, except during construction
   //   where it does not use the main thread specific pump factory.
   //
   enum Type {
     TYPE_DEFAULT,
     TYPE_UI,
+#if defined(OS_LINUX)
+    TYPE_GPU,
+#endif
     TYPE_IO,
 #if defined(OS_ANDROID)
     TYPE_JAVA,
 #endif // defined(OS_ANDROID)
   };
 
   // Normally, it is not necessary to instantiate a MessageLoop.  Instead, it
   // is typical to make use of the current thread's MessageLoop instance.
   explicit MessageLoop(Type type = TYPE_DEFAULT);
   virtual ~MessageLoop();
@@ skipping 419 matching lines @@
   typedef MessagePumpForUI::MessageFilter MessageFilter;
 #endif
 
   MessageLoopForUI() : MessageLoop(TYPE_UI) {
   }
 
   // Returns the MessageLoopForUI of the current thread.
   static MessageLoopForUI* current() {
     MessageLoop* loop = MessageLoop::current();
     DCHECK(loop);
-    DCHECK_EQ(MessageLoop::TYPE_UI, loop->type());
+    // DCHECK_EQ(MessageLoop::TYPE_UI, loop->type());
     return static_cast<MessageLoopForUI*>(loop);
   }
 
 #if defined(OS_WIN)
   void DidProcessMessage(const MSG& message);
 #endif  // defined(OS_WIN)
 
 #if defined(OS_IOS)
   // On iOS, the main message loop cannot be Run().  Instead call Attach(),
   // which connects this MessageLoop to the UI thread's CFRunLoop and allows
@@ skipping 139 matching lines @@
 
 // Do not add any member variables to MessageLoopForIO!  This is important b/c
 // MessageLoopForIO is often allocated via MessageLoop(TYPE_IO).  Any extra
 // data that you need should be stored on the MessageLoop's pump_ instance.
 COMPILE_ASSERT(sizeof(MessageLoop) == sizeof(MessageLoopForIO),
                MessageLoopForIO_should_not_have_extra_member_variables);
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_LOOP_MESSAGE_LOOP_H_