Ensure RenderViewHost is not shut down until a screenshot of the page is taken.

chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc

Index: chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
diff --git a/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc b/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
index 6d47d2b608808c7f73ffb7d3ef40b0532e2f5a38..6aa1ab125e6e1ac8f2f446ba114188c35b600053 100644
--- a/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
+++ b/chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc
@@ -17,10 +17,12 @@
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_process_host_observer.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_iterator.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "content/public/test/browser_test_utils.h"
 
 using content::RenderViewHost;
 using content::RenderWidgetHost;
@@ -111,9 +113,22 @@ class ChromeRenderProcessHostTest : public InProcessBrowserTest {
     content::RenderProcessHost* rph2 = NULL;
     content::RenderProcessHost* rph3 = NULL;
 
-    // Change the first tab to be the omnibox page (TYPE_WEBUI).
+    EXPECT_EQ(host_count, RenderProcessHostCount());
+    ASSERT_EQ(tab_count, browser()->tab_strip_model()->count());
+
+    tab1 = browser()->tab_strip_model()->GetWebContentsAt(tab_count - 1);
+    content::RenderProcessHostWatcher process_watcher(
+        tab1->GetRenderProcessHost(),
+        content::RenderProcessHostWatcher::WATCH_FOR_HOST_DESTRUCTION);
+
+    // Change the first tab to be the omnibox page (TYPE_WEBUI). The navigation
+    // should terminate the existing process.
     GURL omnibox(chrome::kChromeUIOmniboxURL);
     ui_test_utils::NavigateToURL(browser(), omnibox);
+    // Wait for the RPH of the previous page (i.e. starting page) to be
+    // destroyed. The host does not get destroyed until the screenshot of the
+    // page is taken, which may happen after the navigation completes.
+    process_watcher.Wait();
     EXPECT_EQ(tab_count, browser()->tab_strip_model()->count());
     tab1 = browser()->tab_strip_model()->GetWebContentsAt(tab_count - 1);
     rph1 = tab1->GetRenderProcessHost();
@@ -204,9 +219,22 @@ IN_PROC_BROWSER_TEST_F(ChromeRenderProcessHostTest, ProcessPerTab) {
   int tab_count = 1;
   int host_count = 1;
 
+  EXPECT_EQ(tab_count, browser()->tab_strip_model()->count());
+  EXPECT_EQ(host_count, RenderProcessHostCount());
+
+  WebContents* tab1 =
+      browser()->tab_strip_model()->GetWebContentsAt(tab_count - 1);
+  content::RenderProcessHostWatcher process_watcher(
+      tab1->GetRenderProcessHost(),
+      content::RenderProcessHostWatcher::WATCH_FOR_HOST_DESTRUCTION);
+
   // Change the first tab to be the new tab page (TYPE_WEBUI).
   GURL omnibox(chrome::kChromeUIOmniboxURL);
   ui_test_utils::NavigateToURL(browser(), omnibox);
+  // Wait for the RPH of the previous page (i.e. starting page) to be
+  // destroyed. The host does not get destroyed until the screenshot of the
+  // page is taken, which may happen after the navigation completes.
+  process_watcher.Wait();
   EXPECT_EQ(tab_count, browser()->tab_strip_model()->count());
   EXPECT_EQ(host_count, RenderProcessHostCount());