Replace --ppapi-keep-alive-throttle command line switch with IPC parameter.

ppapi/proxy/plugin_globals.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_PROXY_PLUGIN_GLOBALS_H_
 #define PPAPI_PROXY_PLUGIN_GLOBALS_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 119 matching lines @@
   // The embedder should call this function when the command line is known.
   void set_command_line(const std::string& c) { command_line_ = c; }
 
   ResourceReplyThreadRegistrar* resource_reply_thread_registrar() {
     return resource_reply_thread_registrar_.get();
   }
 
   // Interval to limit how many IPC messages are sent indicating that the plugin
   // is active and should be kept alive. The value must be smaller than any
   // threshold used to kill inactive plugins by the embedder host.
-  int keepalive_throttle_interval_milliseconds() const;
-  void set_keepalive_throttle_interval_milliseconds(int i);
+  void set_keepalive_throttle_interval_milliseconds(unsigned i);
 
  private:
   class BrowserSender;
 
   // PpapiGlobals overrides.
   virtual bool IsPluginGlobals() const OVERRIDE;
 
   // Locks the proxy lock and releases the throttle on keepalive IPC messages.
   void OnReleaseKeepaliveThrottle();
 
@@ skipping 24 matching lines @@
   scoped_ptr<base::Thread> file_thread_;
 
   scoped_refptr<ResourceReplyThreadRegistrar> resource_reply_thread_registrar_;
 
   // Indicates activity by the plugin. Used to monitor when a plugin can be
   // shutdown due to idleness. Current needs do not require differentiating
   // between idle state between multiple instances, if any are active they are
   // all considered active.
   bool plugin_recently_active_;
 
-  int keepalive_throttle_interval_milliseconds_;
+  unsigned keepalive_throttle_interval_milliseconds_;
 
   // Member variables should appear before the WeakPtrFactory, see weak_ptr.h.
   base::WeakPtrFactory<PluginGlobals> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginGlobals);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif   // PPAPI_PROXY_PLUGIN_GLOBALS_H_