Fix next_page_id_ in a NTP forced to share an existing WebUI process.

chrome/browser/ui/webui/ntp/new_tab_ui_browsertest.cc

Index: chrome/browser/ui/webui/ntp/new_tab_ui_browsertest.cc
diff --git a/chrome/browser/ui/webui/ntp/new_tab_ui_browsertest.cc b/chrome/browser/ui/webui/ntp/new_tab_ui_browsertest.cc
index e1273293c82ce30d0a98b0743cede34dd0c3c009..8894e6faceb984dccca004887896721267c42845 100644
--- a/chrome/browser/ui/webui/ntp/new_tab_ui_browsertest.cc
+++ b/chrome/browser/ui/webui/ntp/new_tab_ui_browsertest.cc
@@ -3,9 +3,12 @@
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/browser.h"
+#include "chrome/common/url_constants.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "content/browser/tab_contents/tab_contents.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
 #include "googleurl/src/gurl.h"
 
 class NewTabUIBrowserTest : public InProcessBrowserTest {
@@ -28,3 +31,64 @@ IN_PROC_BROWSER_TEST_F(NewTabUIBrowserTest, ChromeInternalLoadsNTP) {
       &empty_inner_html));
   ASSERT_FALSE(empty_inner_html);
 }
+
+// Ensure loading a NTP with an existing SiteInstance in a reused process
+// doesn't cause us to kill the process.  See http://crbug.com/104258.
+IN_PROC_BROWSER_TEST_F(NewTabUIBrowserTest, LoadNTPInExistingProcess) {
+  // Set max renderers to 1 to force running out of processes.
+  RenderProcessHost::SetMaxRendererProcessCountForTest(1);
+
+  // Start server for simple page.
+  ASSERT_TRUE(test_server()->Start());
+
+  // Load a NTP in a new tab.
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(chrome::kChromeUINewTabURL), NEW_FOREGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  EXPECT_EQ(1,
+            browser()->GetTabContentsAt(1)->GetSiteInstance()->max_page_id());
+
+  // Navigate that tab to another site.  This allows the NTP process to exit,
+  // but it keeps the NTP SiteInstance (and its max_page_id) alive in history.
+  {
+    // Wait not just for the navigation to finish, but for the NTP process to
+    // exit as well.
+    ui_test_utils::WindowedNotificationObserver process_exited_observer(
+        content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
+        content::NotificationService::AllSources());
+    browser()->OpenURL(test_server()->GetURL("files/title1.html"), GURL(),
+                       CURRENT_TAB, content::PAGE_TRANSITION_TYPED);
+    process_exited_observer.Wait();
+  }
+
+  // Create and close another two NTPs to inflate the max_page_id.
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(chrome::kChromeUINewTabURL), NEW_FOREGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  EXPECT_EQ(2,
+            browser()->GetTabContentsAt(2)->GetSiteInstance()->max_page_id());
+  browser()->CloseTab();
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(chrome::kChromeUINewTabURL), NEW_FOREGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  EXPECT_EQ(3,
+            browser()->GetTabContentsAt(2)->GetSiteInstance()->max_page_id());
+  browser()->CloseTab();
+
+  // Open another Web UI page in a new tab.
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(chrome::kChromeUISettingsURL), NEW_FOREGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  EXPECT_EQ(1,
+            browser()->GetTabContentsAt(2)->GetSiteInstance()->max_page_id());
+
+  // At this point, opening another NTP will use the old SiteInstance (with a
+  // large max_page_id) in the existing Web UI process (with a small page ID).
+  // Make sure we don't confuse this as an existing navigation to an unknown
+  // entry.
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(chrome::kChromeUINewTabURL), NEW_FOREGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  EXPECT_EQ(4,
+            browser()->GetTabContentsAt(3)->GetSiteInstance()->max_page_id());
+}