NTP: Prevent tab sync icons from being cached.

chrome/browser/ui/webui/chrome_url_data_manager.h

Index: chrome/browser/ui/webui/chrome_url_data_manager.h
diff --git a/chrome/browser/ui/webui/chrome_url_data_manager.h b/chrome/browser/ui/webui/chrome_url_data_manager.h
index 98671bef22023933d97e05a319a515568034c4fd..4c22ea1f13c5ca6aa6a39116d30fd977215569b5 100644
--- a/chrome/browser/ui/webui/chrome_url_data_manager.h
+++ b/chrome/browser/ui/webui/chrome_url_data_manager.h
@@ -107,6 +107,9 @@ class ChromeURLDataManager : public ProfileKeyedService {
     // TODO: nuke this and convert all callers to not replace.
     virtual bool ShouldReplaceExistingSource() const;
 
+    // Returns true if responses from this DataSource can be cached.
+    virtual bool AllowCaching() const { return true; }
+
     static void SetFontAndTextDirection(
         base::DictionaryValue* localized_strings);