Introduce RenderProcessHostObserver, use it in its first client.

content/public/browser/render_process_host.h

Index: content/public/browser/render_process_host.h
diff --git a/content/public/browser/render_process_host.h b/content/public/browser/render_process_host.h
index 3aedc59ed4b8dc722dfb483e70cc3d722e03688c..daf754cda2ede73cd04768721a3c31c8b57e20a1 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -26,6 +26,7 @@ class TimeDelta;
 namespace content {
 class BrowserContext;
 class BrowserMessageFilter;
+class RenderProcessHostObserver;
 class RenderWidgetHost;
 class StoragePartition;
 
@@ -55,6 +56,8 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
     int exit_code;
   };
 
+  // General functions ---------------------------------------------------------
+
   virtual ~RenderProcessHost() {}
 
   // Initialize the new renderer process, returning true on success. This must
@@ -73,6 +76,12 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   virtual void AddRoute(int32 routing_id, IPC::Listener* listener) = 0;
   virtual void RemoveRoute(int32 routing_id) = 0;
 
+  // Add and remove observers for lifecycle events. The order in which
+  // notifications are sent to observers is undefined. Observers must be sure to
+  // remove the observer before they go away.
+  virtual void AddObserver(RenderProcessHostObserver* observer) = 0;
+  virtual void RemoveObserver(RenderProcessHostObserver* observer) = 0;
+
   // Called to wait for the next UpdateRect message for the specified render
   // widget.  Returns true if successful, and the msg out-param will contain a
   // copy of the received UpdateRect message.
@@ -216,6 +225,9 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   // modifies the current process' command line.
   static void SetRunRendererInProcess(bool value);
 
+  // This forces a renderer that is running "in process" to shut down.
+  static void ShutDownInProcessRenderer();

[jam, 2013/11/18 19:16:20]

nit: since this is only called inside content, put this on
RenderProcessHostImpl. then you can get rid of the "friend" in
render_process_host_impl.h

[Avi (use Gerrit), 2013/11/18 19:22:21]

Right. I was thinking BrowserMainLoop was in chrome/.

+
   // Allows iteration over all the RenderProcessHosts in the browser. Note
   // that each host may not be active, and therefore may have NULL channels.
   static iterator AllHostsIterator();