Hook up the SequencedWorkerPool to the browser thread.

content/public/browser/browser_thread.h

Index: content/public/browser/browser_thread.h
===================================================================
--- content/public/browser/browser_thread.h	(revision 116082)
+++ content/public/browser/browser_thread.h	(working copy)
@@ -21,6 +21,7 @@
 class MessageLoop;
 
 namespace base {
+class SequencedWorkerPool;
 class Thread;
 }
 
@@ -157,6 +158,11 @@
         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);