Remove IOThread::message_loop().

chrome/browser/browser_process.h

Index: chrome/browser/browser_process.h
diff --git a/chrome/browser/browser_process.h b/chrome/browser/browser_process.h
index 8cb0e378c2ed55162731f9662e7521b44b74ee51..faaa90cede06eb67b149dc4c13b07ee271294b05 100644
--- a/chrome/browser/browser_process.h
+++ b/chrome/browser/browser_process.h
@@ -134,9 +134,6 @@ class BrowserProcess {
   // database. History has its own thread since it has much higher traffic.
   virtual base::Thread* db_thread() = 0;
 
-  // Returns the thread that is used for background cache operations.
-  virtual base::Thread* cache_thread() = 0;
-
   // Returns the thread that is used for health check of all browser threads.
   virtual WatchDogThread* watchdog_thread() = 0;