Clean up RenderViewHostManager swapping logic.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 3552195c8aac15a3d0601de99ea8149239da6f50..f356c05deb15d71fd00dc1fd9ce16b3a13500971 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -267,6 +267,21 @@ bool IsIsolatedAppInProcess(const GURL& site_url,
   return false;
 }
 
+// If |url| has an extension or isolated app (not a hosted app) associated with
+// it, return it.  Otherwise return null.
+const Extension* GetExtensionOrIsolatedApp(const GURL& url,
+                                           ExtensionService* service) {
+  const Extension* extension =
+      service->extensions()->GetExtensionOrAppByURL(ExtensionURLInfo(url));
+  // Ignore hosted apps that aren't isolated apps.
+  if (extension &&
+      extension->is_hosted_app() &&
+      !extension->is_storage_isolated())
+    extension = NULL;
+  return extension;
+}
+
+
 bool CertMatchesFilter(const net::X509Certificate& cert,
                        const base::DictionaryValue& filter) {
   // TODO(markusheintz): This is the minimal required filter implementation.
@@ -647,28 +662,29 @@ void ChromeContentBrowserClient::SiteInstanceDeleting(
                  site_instance->GetId()));
 }
 
-bool ChromeContentBrowserClient::ShouldSwapProcessesForNavigation(
+bool ChromeContentBrowserClient::ShouldSwapBrowsingInstanceForNavigation(
+    content::BrowserContext* browser_context,
     const GURL& current_url,
     const GURL& new_url) {
-  if (current_url.is_empty()) {
-    // Always choose a new process when navigating to extension URLs. The
-    // process grouping logic will combine all of a given extension's pages
-    // into the same process.
-    if (new_url.SchemeIs(chrome::kExtensionScheme))
-      return true;
-
+  Profile* profile = Profile::FromBrowserContext(browser_context);
+  ExtensionService* service = profile->GetExtensionService();
+  if (!service)
     return false;
-  }
 
-  // Also, we must switch if one is an extension and the other is not the exact
-  // same extension.
-  if (current_url.SchemeIs(chrome::kExtensionScheme) ||
-      new_url.SchemeIs(chrome::kExtensionScheme)) {
-    if (current_url.GetOrigin() != new_url.GetOrigin())
-      return true;
-  }
-
-  return false;
+  // We must use a new BrowsingInstance (forcing a process swap and disabling
+  // scripting by existing tabs) if one of the URLs is an extension and the
+  // other is not the exact same extension.
+  //
+  // We ignore hosted apps here so that other tabs in their BrowsingInstance can
+  // script them.  Navigations to/from a hosted app will still trigger a
+  // SiteInstance swap in RenderViewHostManager.
+  //
+  // However, we do use a new BrowsingInstance for isolated apps, which should
+  // not be scriptable by other tabs.
+  const Extension* current_extension =
+      GetExtensionOrIsolatedApp(current_url, service);
+  const Extension* new_extension = GetExtensionOrIsolatedApp(new_url, service);
+  return current_extension != new_extension;
 }
 
 bool ChromeContentBrowserClient::ShouldSwapProcessesForRedirect(