[content shell] protect against the case when a RPH dies before the process launched

e.g.
http/tests/xmlhttprequest/access-control-repeated-failed-preflight-crash.html
quickly opens and closes the devtools. If a new RPH is then created and happens
to be at the same location, we'll register twice for the process created
notification.

BUG=111316
R=marja@chromium.org

Review URL: https://chromiumcodereview.appspot.com/16023012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202465 0039d316-1c4b-4281-b951-d872f2087c98

content/shell/shell_content_browser_client.cc

@@ -91,6 +91,9 @@ void ShellContentBrowserClient::RenderProcessHostCreated(
   registrar_.Add(this,
                  NOTIFICATION_RENDERER_PROCESS_CREATED,
                  Source<RenderProcessHost>(host));
+  registrar_.Add(this,
+                 NOTIFICATION_RENDERER_PROCESS_TERMINATED,
+                 Source<RenderProcessHost>(host));
 }
 
 net::URLRequestContextGetter* ShellContentBrowserClient::CreateRequestContext(
@@ -212,6 +215,9 @@ void ShellContentBrowserClient::Observe(int type,
       registrar_.Remove(this,
                         NOTIFICATION_RENDERER_PROCESS_CREATED,
                         source);
+      registrar_.Remove(this,
+                        NOTIFICATION_RENDERER_PROCESS_TERMINATED,
+                        source);
       if (hyphen_dictionary_file_ != base::kInvalidPlatformFileValue) {
         RenderProcessHost* host = Source<RenderProcessHost>(source).ptr();
         IPC::PlatformFileForTransit file = IPC::GetFileHandleForProcess(
@@ -221,6 +227,16 @@ void ShellContentBrowserClient::Observe(int type,
       break;
     }
 
+    case NOTIFICATION_RENDERER_PROCESS_TERMINATED: {
+      registrar_.Remove(this,
+                        NOTIFICATION_RENDERER_PROCESS_CREATED,
+                        source);
+      registrar_.Remove(this,
+                        NOTIFICATION_RENDERER_PROCESS_TERMINATED,
+                        source);
+      break;
+    }
+
     default:
       NOTREACHED();
   }