Merge 138112 - NTP: Prevent tab sync icons from being cached.

chrome/browser/ui/webui/session_favicon_source.cc

Index: chrome/browser/ui/webui/session_favicon_source.cc
===================================================================
--- chrome/browser/ui/webui/session_favicon_source.cc	(revision 140618)
+++ chrome/browser/ui/webui/session_favicon_source.cc	(working copy)
@@ -49,3 +49,9 @@
   // requests on the floor.
   return false;
 }
+
+bool SessionFaviconSource::AllowCaching() const {
+  // Prevent responses from being cached, otherwise session favicons won't
+  // update in a timely manner.
+  return false;
+}