Re-fix http://crbug.com/87176, and add a test.

content/browser/renderer_host/render_process_host_browsertest.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/common/child_process_messages.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/test_notification_tracker.h"
+#include "content/shell/shell.h"
+#include "content/test/content_browser_test.h"
+#include "content/test/content_browser_test_utils.h"
+#include "net/test/embedded_test_server/embedded_test_server.h"
+
+namespace content {
+namespace {
+
+class RenderProcessHostTest : public ContentBrowserTest {};
+
+// Sometimes the renderer process's ShutdownRequest (corresponding to the
+// ViewMsg_WasSwappedOut from a previous navigation) doesn't arrive until after
+// the browser process decides to re-use the renderer for a new purpose.  This
+// test makes sure the browser doesn't let the renderer die in that case.  See
+// http://crbug.com/87176.
+IN_PROC_BROWSER_TEST_F(RenderProcessHostTest,
+                       ShutdownRequestFromActiveTabIgnored) {
+  ASSERT_TRUE(embedded_test_server()->InitializeAndWaitUntilReady());
+
+  GURL test_url = embedded_test_server()->GetURL("/simple_page.html");
+  NavigateToURL(shell(), test_url);
+  RenderProcessHost* rph =
+      shell()->web_contents()->GetRenderViewHost()->GetProcess();
+
+  TestNotificationTracker termination_watcher;
+  termination_watcher.ListenFor(NOTIFICATION_RENDERER_PROCESS_CLOSED,
+                                Source<RenderProcessHost>(rph));
+  ChildProcessHostMsg_ShutdownRequest msg;
+  rph->OnMessageReceived(msg);
+
+  // If the RPH sends a mistaken ChildProcessMsg_Shutdown, the renderer process
+  // will take some time to die. Wait for a second tab to load in order to give
+  // that time to happen.
+  NavigateToURL(CreateBrowser(), test_url);
+
+  EXPECT_EQ(0U, termination_watcher.size());
+}
+
+}  // namespace
+}  // namespace content