Move process-per-site logic from BrowsingInstance to RenderProcessHost.

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

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
@@ skipping 64 matching lines @@
       ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
   EXPECT_EQ(1, browser()->GetWebContentsAt(2)->GetMaxPageID());
   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()->GetWebContentsAt(2)->GetMaxPageID());
 
-  // At this point, opening another NTP will use the old SiteInstance in the
-  // existing Web UI process, but the page IDs shouldn't affect each other.
+  // At this point, opening another NTP will use the existing WebUI process
+  // but its own SiteInstance, so the page IDs shouldn't affect each other.
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), GURL(chrome::kChromeUINewTabURL), NEW_FOREGROUND_TAB,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
   EXPECT_EQ(1, browser()->GetWebContentsAt(3)->GetMaxPageID());
 
-  // Only navigating to the NTP in the original tab should have a higher
-  // page ID.
+  // Navigating to the NTP in the original tab causes a BrowsingInstance
+  // swap, so it gets a new SiteInstance starting with page ID 1 again.
   browser()->ActivateTabAt(1, true);
   ui_test_utils::NavigateToURL(browser(), GURL(chrome::kChromeUINewTabURL));
-  EXPECT_EQ(2, browser()->GetWebContentsAt(1)->GetMaxPageID());
+  EXPECT_EQ(1, browser()->GetWebContentsAt(1)->GetMaxPageID());
 }
 
 // Loads chrome://hang/ into two NTP tabs, ensuring we don't crash.
 // See http://crbug.com/59859.
 // If this flakes, use http://crbug.com/87200.
 IN_PROC_BROWSER_TEST_F(NewTabUIBrowserTest, ChromeHangInNTP) {
   // Bring up a new tab page.
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), GURL(chrome::kChromeUINewTabURL), NEW_FOREGROUND_TAB,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
@@ skipping 37 matching lines @@
 
   // We don't use ui_test_utils::NavigateToURLWithDisposition because that waits
   // for current loading to stop.
   content::TestNavigationObserver observer(
       content::NotificationService::AllSources());
   browser()->OpenURL(OpenURLParams(
       GURL("data:text/html,hello world"), Referrer(), CURRENT_TAB,
       content::PAGE_TRANSITION_TYPED, false));
   observer.Wait();
 }