Linux: move X operations from the IO to UI2 thread.

chrome/browser/chrome_thread.h

 // Copyright (c) 2006-2008 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 CHROME_BROWSER_CHROME_THREAD_H__
 #define CHROME_BROWSER_CHROME_THREAD_H__
 
 #include "base/lock.h"
 #include "base/thread.h"
 
@@ skipping 20 matching lines @@
   enum ID {
     // This is the thread that processes IPC and network messages.
     IO,
 
     // This is the thread that interacts with the file system.
     FILE,
 
     // This is the thread that interacts with the database.
     DB,
 
+    // This is the thread that interacts with the history database.
+    HISTORY,
+
+#if defined(OS_LINUX)
+    // This thread has a second connection to the X server and is used to
+    // process UI requests when routing the request to the UI thread would risk
+    // deadlock.
+    BACKGROUND_X11,
+#endif
+
     // This identifier does not represent a thread.  Instead it counts the
     // number of well-known threads.  Insert new well-known threads before this
     // identifier.
     ID_COUNT
   };
 
   // Construct a ChromeThread with the supplied identifier.  It is an error
   // to construct a ChromeThread that already exists.
   explicit ChromeThread(ID identifier);
   virtual ~ChromeThread();
@@ skipping 17 matching lines @@
   static Lock lock_;
 
   // An array of the ChromeThread objects.  This array is protected by |lock_|.
   // The threads are not owned by this array.  Typically, the threads are owned
   // on the UI thread by the g_browser_process object.  ChromeThreads remove
   // themselves from this array upon destruction.
   static ChromeThread* chrome_threads_[ID_COUNT];
 };
 
 #endif  // #ifndef CHROME_BROWSER_CHROME_THREAD_H__