Update Java Bridge to use its own thread in the browser process

content/browser/browser_main_loop.cc

 // Copyright (c) 2011 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 "content/browser/browser_main_loop.h"
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 325 matching lines @@
         options = &io_message_loop_options;
 #endif
         break;
       case BrowserThread::PROCESS_LAUNCHER:
         thread_to_start = &process_launcher_thread_;
         break;
       case BrowserThread::CACHE:
         thread_to_start = &cache_thread_;
         options = &io_message_loop_options;
         break;
+      case BrowserThread::JAVA_BRIDGE:
+#if defined(ENABLE_JAVA_BRIDGE)
+        thread_to_start = &java_bridge_thread_;
+#endif
+        break;
       case BrowserThread::IO:
         thread_to_start = &io_thread_;
         options = &io_message_loop_options;
         break;
 #if defined(OS_CHROMEOS)
       case BrowserThread::WEB_SOCKET_PROXY:
         thread_to_start = &web_socket_proxy_thread_;
         options = &io_message_loop_options;
         break;
 #endif
       case BrowserThread::UI:
       case BrowserThread::ID_COUNT:
       default:
         NOTREACHED();
         break;
     }
 
     BrowserThread::ID id = static_cast<BrowserThread::ID>(thread_id);
 
     if (parts_.get())
       parts_->PreStartThread(id);
 
     if (thread_id == BrowserThread::WEBKIT) {
       webkit_thread_.reset(new WebKitThread);
       webkit_thread_->Initialize();
     } else if (thread_to_start) {
       (*thread_to_start).reset(new BrowserProcessSubThread(id));
       (*thread_to_start)->StartWithOptions(*options);
-    } else {
-      NOTREACHED();
     }
 
     if (parts_.get())
       parts_->PostStartThread(id);
   }
 
   if (parts_.get())
     parts_->PreMainMessageLoopRun();
 
   TRACE_EVENT_BEGIN_ETW("BrowserMain:MESSAGE_LOOP", 0, "");
@@ skipping 36 matching lines @@
     // BrowserThread IDs and DCHECKing on a missing case in the switch
     // statement helps avoid a mismatch between this code and the
     // BrowserThread::ID enumeration.
     //
     // The destruction order is the reverse order of occurrence in the
     // BrowserThread::ID list. The rationale for the order is as
     // follows (need to be filled in a bit):
     //
     // - (Not sure why the WEB_SOCKET_PROXY thread is stopped first.)
     //
+    // - The JAVA_BRIDGE thread receives messages from the UI thread, and posts
+    //   messages to and receives messages from the IO thread. Of the
+    //   interactions with the IO thread, receiving messages is more common, so
+    //   make sure this thread outlives the IO thread to take advantage of the
+    //   optimization in BrowserThread.
+    //
     // - The IO thread is the only user of the CACHE thread.
     //
     // - The PROCESS_LAUNCHER thread must be stopped after IO in case
     //   the IO thread posted a task to terminate a process on the
     //   process launcher thread.
     //
     // - (Not sure why FILE needs to stop before WEBKIT.)
     //
     // - The WEBKIT thread (which currently is the responsibility of
     //   the embedder to stop, by destroying ResourceDispatcherHost
@@ skipping 14 matching lines @@
         break;
       case BrowserThread::FILE:
         thread_to_stop = &file_thread_;
         break;
       case BrowserThread::PROCESS_LAUNCHER:
         thread_to_stop = &process_launcher_thread_;
         break;
       case BrowserThread::CACHE:
         thread_to_stop = &cache_thread_;
         break;
+      case BrowserThread::JAVA_BRIDGE:
+#if defined(ENABLE_JAVA_BRIDGE)
+        thread_to_stop = &java_bridge_thread_;
+#endif
+        break;
       case BrowserThread::IO:
         thread_to_stop = &io_thread_;
         break;
 #if defined(OS_CHROMEOS)
       case BrowserThread::WEB_SOCKET_PROXY:
         thread_to_stop = &web_socket_proxy_thread_;
         break;
 #endif
       case BrowserThread::UI:
       case BrowserThread::ID_COUNT:
       default:
         NOTREACHED();
         break;
     }
 
     BrowserThread::ID id = static_cast<BrowserThread::ID>(thread_id);
 
     if (parts_.get())
       parts_->PreStopThread(id);
 
     if (id == BrowserThread::WEBKIT) {
       webkit_thread_.reset();
     } else if (thread_to_stop) {
       thread_to_stop->reset();
-    } else {
-      NOTREACHED();
     }
 
     if (parts_.get())
       parts_->PostStopThread(id);
   }
 
   if (parts_.get())
     parts_->PostDestroyThreads();
 }
 
@@ skipping 52 matching lines @@
     MessageLoopForUI::current()->PostTask(FROM_HERE, parameters_.ui_task);
 
 #if defined(OS_MACOSX)
   MessageLoopForUI::current()->Run();
 #else
   MessageLoopForUI::current()->RunWithDispatcher(NULL);
 #endif
 }
 
 }  // namespace content