Keep event page alive when there's some Pepper plugin on it.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index ee61fc7914ac8e404edb43536bc67e155d4331f0..cbea034753290340fa6d3f5be780c35c413cb5a9 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -537,6 +537,10 @@ bool WebContentsImpl::OnMessageReceived(RenderViewHost* render_view_host,
     IPC_MESSAGE_HANDLER(ViewHostMsg_AppCacheAccessed, OnAppCacheAccessed)
     IPC_MESSAGE_HANDLER(ViewHostMsg_WebUISend, OnWebUISend)
 #if defined(ENABLE_PLUGINS)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_PepperInstanceCreated,
+                        OnPepperInstanceCreated)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_PepperInstanceDeleted,
+                        OnPepperInstanceDeleted)
     IPC_MESSAGE_HANDLER(FrameHostMsg_PepperPluginHung, OnPepperPluginHung)
     IPC_MESSAGE_HANDLER(FrameHostMsg_PluginCrashed, OnPluginCrashed)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RequestPpapiBrokerPermission,
@@ -3012,6 +3016,14 @@ void WebContentsImpl::OnWebUISend(const GURL& source_url,
 }
 
 #if defined(ENABLE_PLUGINS)
+void WebContentsImpl::OnPepperInstanceCreated() {
+  FOR_EACH_OBSERVER(WebContentsObserver, observers_, PepperInstanceCreated());
+}
+
+void WebContentsImpl::OnPepperInstanceDeleted() {
+  FOR_EACH_OBSERVER(WebContentsObserver, observers_, PepperInstanceDeleted());
+}
+
 void WebContentsImpl::OnPepperPluginHung(int plugin_child_id,
                                          const base::FilePath& path,
                                          bool is_hung) {