Hook up the SequencedWorkerPool to the browser thread.

content/public/browser/browser_thread.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_BROWSER_THREAD_H_
 #define CONTENT_PUBLIC_BROWSER_BROWSER_THREAD_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/message_loop_proxy.h"
 #include "base/task.h"
 #include "base/tracked_objects.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/browser_thread_delegate.h"
 
 #if defined(UNIT_TEST)
 #include "base/logging.h"
 #endif  // UNIT_TEST
 
 class MessageLoop;
 
 namespace base {
+class SequencedWorkerPool;
 class Thread;
 }
 
 namespace content {
 
 class BrowserThreadImpl;
 
 ///////////////////////////////////////////////////////////////////////////////
 // BrowserThread
 //
@@ skipping 116 matching lines @@
   }
 
   template <class T>
   static bool ReleaseSoon(ID identifier,
                           const tracked_objects::Location& from_here,
                           const T* object) {
     return GetMessageLoopProxyForThread(identifier)->ReleaseSoon(
         from_here, object);
   }
 
+  // Returns the thread pool used for blocking file I/O. Use this object to
+  // perform random blocking operations such as file writes or querying the
+  // Windows registry.
+  static base::SequencedWorkerPool* GetBlockingPool();

[jam, 2012/01/03 19:48:17]

does this getter really belong on BrowserThread? it seems unrelated to the other
threads, since those use a very different model (i.e. BT::PostTask(UI, ...)) vs
this

+
   // Callable on any thread.  Returns whether the given ID corresponds to a well
   // known thread.
   static bool IsWellKnownThread(ID identifier);
 
   // Callable on any thread.  Returns whether you're currently on a particular
   // thread.
   static bool CurrentlyOn(ID identifier);
 
   // Callable on any thread.  Returns whether the threads message loop is valid.
   // If this returns false it means the thread is in the process of shutting
@@ skipping 74 matching lines @@
  private:
   friend class BrowserThreadImpl;
 
   BrowserThread() {}
   DISALLOW_COPY_AND_ASSIGN(BrowserThread);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_BROWSER_THREAD_H_