Verify that the RPH is still alive when handling incoming Notification IPCs.

The NotificationMessageFilter still receives a number of IPC messages on
the UI thread. It is possible that the IPC message gets handled after
the profile has been shut down, so make sure that this isn't the case
by verifying that the RenderProcessHost still exists.

BUG=457590

Review URL: https://codereview.chromium.org/1023633003

Cr-Commit-Position: refs/heads/master@{#321421}

content/browser/notifications/notification_message_filter.cc

@@ -13,6 +13,7 @@
 #include "content/public/browser/desktop_notification_delegate.h"
 #include "content/public/browser/platform_notification_context.h"
 #include "content/public/browser/platform_notification_service.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/common/content_client.h"
 
 namespace content {
@@ -81,6 +82,10 @@ void NotificationMessageFilter::OnShowPlatformNotification(
     const GURL& origin,
     const SkBitmap& icon,
     const PlatformNotificationData& notification_data) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!RenderProcessHost::FromID(process_id_))
+    return;
+
   scoped_ptr<DesktopNotificationDelegate> delegate(
       new PageNotificationDelegate(process_id_, notification_id));
 
@@ -109,6 +114,8 @@ void NotificationMessageFilter::OnShowPersistentNotification(
     const SkBitmap& icon,
     const PlatformNotificationData& notification_data) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!RenderProcessHost::FromID(process_id_))
+    return;
 
   PlatformNotificationService* service =
       GetContentClient()->browser()->GetPlatformNotificationService();
@@ -124,6 +131,10 @@ void NotificationMessageFilter::OnShowPersistentNotification(
 
 void NotificationMessageFilter::OnClosePlatformNotification(
     int notification_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!RenderProcessHost::FromID(process_id_))
+    return;
+
   if (!close_closures_.count(notification_id))
     return;
 
@@ -135,6 +146,8 @@ void NotificationMessageFilter::OnClosePersistentNotification(
     const GURL& origin,
     const std::string& persistent_notification_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!RenderProcessHost::FromID(process_id_))
+    return;
 
   PlatformNotificationService* service =
       GetContentClient()->browser()->GetPlatformNotificationService();