IDL: Remove support for [LogPreviousValue] extended attribute

public/web/WebDOMActivityLogger.h

Index: public/web/WebDOMActivityLogger.h
diff --git a/public/web/WebDOMActivityLogger.h b/public/web/WebDOMActivityLogger.h
index afad4c8e98e5a184df1fa786b19e46fda0ee7566..27958a5e47af0e98eef8f1fec80b9cff204695a5 100644
--- a/public/web/WebDOMActivityLogger.h
+++ b/public/web/WebDOMActivityLogger.h
@@ -44,7 +44,6 @@ public:
 
     virtual void logGetter(const WebString& apiName, const WebURL& url, const WebString& title) { }
     virtual void logSetter(const WebString& apiName, const v8::Handle<v8::Value>& newValue, const WebURL& url, const WebString& title) { }
-    virtual void logSetter(const WebString& apiName, const v8::Handle<v8::Value>& newValue, const v8::Handle<v8::Value>& oldValue, const WebURL& url, const WebString& title) { }

[Jens Widell, 2014/08/27 11:57:38]

This is implemented in extensions/renderer/dom_activity_logger.cc, but not using
OVERRIDE, so removing it here will not break compilation (or change behavior.)

     virtual void logMethod(const WebString& apiName, int argc, const v8::Handle<v8::Value>* argv, const WebURL& url, const WebString& title) { }
     virtual void logEvent(const WebString& eventName, int argc, const WebString* argv, const WebURL& url, const WebString& title) { }
 };