Shortcut a couple of IPCs when the task manager is disabled.

chrome/browser/task_manager/task_manager.h

Index: chrome/browser/task_manager/task_manager.h
diff --git a/chrome/browser/task_manager/task_manager.h b/chrome/browser/task_manager/task_manager.h
index 8c0fee679c687aea1be436b10410150032b00a28..76ce114c10c0725010b3dad96266c64965ac1566 100644
--- a/chrome/browser/task_manager/task_manager.h
+++ b/chrome/browser/task_manager/task_manager.h
@@ -450,6 +450,9 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
   // for each one is expensive.
   void NotifyMultipleBytesRead();
 
+  // Called on the IO thread to start/stop updating byte counts.
+  void SetUpdatingByteCount(bool is_updating);
+
   // Returns the network usage (in byte per second) that should be displayed for
   // the passed |resource|.  -1 means the information is not available for that
   // resource.
@@ -533,6 +536,10 @@ class TaskManagerModel : public base::RefCountedThreadSafe<TaskManagerModel> {
   // Whether we are currently in the process of updating.
   UpdateState update_state_;
 
+  // Whether the IO thread is currently in the process of updating; accessed
+  // only on the IO thread.
+  bool is_updating_byte_count_;
+
   // A salt lick for the goats.
   uint64 goat_salt_;