Add the feature to retain the user gesture in the extension callback

chrome/browser/renderer_host/pepper/pepper_extensions_common_message_filter.h

Index: chrome/browser/renderer_host/pepper/pepper_extensions_common_message_filter.h
===================================================================
--- chrome/browser/renderer_host/pepper/pepper_extensions_common_message_filter.h	(revision 262146)
+++ chrome/browser/renderer_host/pepper/pepper_extensions_common_message_filter.h	(working copy)
@@ -87,7 +87,8 @@
       scoped_ptr<ppapi::host::ReplyMessageContext> reply_context,
       ExtensionFunction::ResponseType type,
       const base::ListValue& results,
-      const std::string& error);
+      const std::string& error,
+      const bool response_user_gesture);

[not at google - send to devlin, 2014/04/07 22:09:09]

just |user_gesture| is fine, everywhere else too.

[wjywbs, 2014/04/08 13:24:42]

I thought |user_gesture| is defined in extension_function.h, so
|response_user_gesture| can distinct with it. I can change
|response_user_gesture| to |user_gesture| outside extension_function.h

[not at google - send to devlin, 2014/04/08 16:01:10]

Yeah the only place where you'd need to have a different name is in
extension_function. It's a bit confusing with respect to the "user_gesture"
property. Perhaps we should call response_user_gesture more
"retain_user_gesture"; it's much the same, but clearer what is going on (and
idiomatically more restrictive).

 
   bool HandleRequest(ppapi::host::HostMessageContext* context,
                      const std::string& request_name,