Don't notify the task manager about bytes read from the cache.

chrome/browser/net/chrome_network_delegate.cc

Index: chrome/browser/net/chrome_network_delegate.cc
diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index 747f670bfc10b753149a2e07a67728e818375ee4..6c99b196aa868b22467b16740165420548aad424 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -538,7 +538,10 @@ void ChromeNetworkDelegate::OnRawBytesRead(const net::URLRequest& request,
       request, bytes_read);
 
 #if defined(ENABLE_TASK_MANAGER)
-  TaskManager::GetInstance()->model()->NotifyBytesRead(request, bytes_read);
+  // This is not completely accurate, but as a first approximation ignore
+  // requests that are served from the cache. See bug 330931 for more info.
+  if (!request.was_cached())
+    TaskManager::GetInstance()->model()->NotifyBytesRead(request, bytes_read);
 #endif  // defined(ENABLE_TASK_MANAGER)
 }