plugins: use OnChannelError to detect when the channel goes away

chrome/common/child_process_host.h

Index: chrome/common/child_process_host.h
diff --git a/chrome/common/child_process_host.h b/chrome/common/child_process_host.h
index caabe66e3f5294265e36cea0aacf88359d4ea7ad..3b97200ee9bc17c0479c816dd8dbea088e0aac38 100644
--- a/chrome/common/child_process_host.h
+++ b/chrome/common/child_process_host.h
@@ -10,7 +10,6 @@
 
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
-#include "base/waitable_event_watcher.h"
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 #include "chrome/common/ipc_channel.h"
 
@@ -19,7 +18,6 @@ class NotificationType;
 // Plugins/workers and other child processes that live on the IO thread should
 // derive from this class.
 class ChildProcessHost : public ResourceDispatcherHost::Receiver,
-                         public base::WaitableEventWatcher::Delegate,
                          public IPC::Channel::Listener {
  public:
   virtual ~ChildProcessHost();
@@ -78,8 +76,8 @@ class ChildProcessHost : public ResourceDispatcherHost::Receiver,
   // Sends the given notification to the notification service on the UI thread.
   void Notify(NotificationType type);
 
-  // WaitableEventWatcher::Delegate implementation:
-  virtual void OnWaitableEventSignaled(base::WaitableEvent *event);
+  // Called when the child process goes away.
+  void OnChildDied();
 
   // By using an internal class as the IPC::Channel::Listener, we can intercept
   // OnMessageReceived/OnChannelConnected and do our own processing before
@@ -106,11 +104,6 @@ class ChildProcessHost : public ResourceDispatcherHost::Receiver,
 
   // IPC Channel's id.
   std::string channel_id_;
-
-  // Used to watch the child process handle.
-  base::WaitableEventWatcher watcher_;
-
-  scoped_ptr<base::WaitableEvent> process_event_;
 };
 
 #endif  // CHROME_COMMON_CHILD_PROCESS_HOST_H_