DevTools: fix co-existance of multiple DevTools extensions

Source/web/WebDevToolsFrontendImpl.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 75 matching lines @@
         v8::Handle<v8::Object> global = scriptState->context()->Global();
         v8::Handle<v8::Value> devtoolsHostObj = toV8(m_devtoolsHost.get(), global, scriptState->isolate());
         global->Set(v8::String::NewFromUtf8(isolate, "DevToolsHost"), devtoolsHostObj);
     }
 
     if (m_injectedScriptForOrigin.isEmpty())
         return;
 
     String origin = frame->securityOrigin().toString();
     String script = m_injectedScriptForOrigin.get(origin);
-    if (!script.isEmpty())
-        frame->frame()->script().executeScriptInMainWorld(script + "()");
+    if (script.isEmpty())
+        return;
+    static int s_lastScriptId = 0;
+    StringBuilder scriptWithId;
+    scriptWithId.append(script);
+    scriptWithId.append('(');
+    scriptWithId.appendNumber(++s_lastScriptId);
+    scriptWithId.append(')');
+    frame->frame()->script().executeScriptInMainWorld(scriptWithId.toString());
 }
 
 void WebDevToolsFrontendImpl::sendMessageToBackend(const String& message)
 {
     if (m_client)
         m_client->sendMessageToBackend(message);
 }
 
 void WebDevToolsFrontendImpl::sendMessageToEmbedder(const String& message)
 {
@@ skipping 10 matching lines @@
 {
     WebLocalFrameImpl::fromFrame(targetFrame)->viewImpl()->showContextMenuAtPoint(x, y, menuProvider);
 }
 
 void WebDevToolsFrontendImpl::setInjectedScriptForOrigin(const String& origin, const String& source)
 {
     m_injectedScriptForOrigin.set(origin, source);
 }
 
 } // namespace blink