Refactor NaClProcessHost. Reduce chances to leak the resource.

components/nacl/browser/nacl_process_host.h

Index: components/nacl/browser/nacl_process_host.h
diff --git a/components/nacl/browser/nacl_process_host.h b/components/nacl/browser/nacl_process_host.h
index 324db114e0201e94ac9686688618cc961a3c83b4..ce09d6b22ea705c1515c96828c631e92f075b882 100644
--- a/components/nacl/browser/nacl_process_host.h
+++ b/components/nacl/browser/nacl_process_host.h
@@ -112,6 +112,8 @@ class NaClProcessHost : public content::BrowserChildProcessHostDelegate {
   content::BrowserPpapiHost* browser_ppapi_host() { return ppapi_host_.get(); }
 
  private:
+  class ScopedChannelHandle;
+
   void LaunchNaClGdb();
 
   // Mark the process as using a particular GDB debug stub port and notify
@@ -142,18 +144,17 @@ class NaClProcessHost : public content::BrowserChildProcessHostDelegate {
   bool enable_ppapi_proxy() { return render_view_id_ != 0; }
 
   // Sends the reply message to the renderer who is waiting for the plugin
-  // to load. Returns true on success.
-  bool ReplyToRenderer(
-      const IPC::ChannelHandle& ppapi_channel_handle,
-      const IPC::ChannelHandle& trusted_channel_handle,
-      const IPC::ChannelHandle& manifest_service_channel_handle);
+  // to load.
+  void ReplyToRenderer(ScopedChannelHandle ppapi_channel_handle,
+                       ScopedChannelHandle trusted_channel_handle,
+                       ScopedChannelHandle manifest_service_channel_handle);
 
   // Sends the reply with error message to the renderer.
   void SendErrorToRenderer(const std::string& error_message);
 
   // Sends the reply message to the renderer. Either result or
   // error message must be empty.
-  void SendMessageToRenderer(const NaClLaunchResult& result,
+  bool SendMessageToRenderer(const NaClLaunchResult& result,
                              const std::string& error_message);
 
   // Sends the message to the NaCl process to load the plugin. Returns true