Modify --isolate-extensions to not isolate hosted apps.

content/browser/site_instance_impl.h

Index: content/browser/site_instance_impl.h
diff --git a/content/browser/site_instance_impl.h b/content/browser/site_instance_impl.h
index 3bbaf337544a187e71b16a8f932d9fb0f800d3eb..cc260c50d73d152ff6864851d2d5eff6974db746 100644
--- a/content/browser/site_instance_impl.h
+++ b/content/browser/site_instance_impl.h
@@ -85,6 +85,15 @@ class CONTENT_EXPORT SiteInstanceImpl : public SiteInstance,
   static GURL GetEffectiveURL(BrowserContext* browser_context,
                               const GURL& url);
 
+  // Returns true if pages loaded from |effective_url| ought to be handled only
+  // by a renderer process isolated from other sites. If --site-per-process is
+  // on the command line, this is true for all sites. In other site isolation
+  // modes, only a subset of sites will require dedicated processes.
+  //
+  // |effective_url| must be an effective URL.
+  static bool DoesSiteRequireDedicatedProcess(BrowserContext* browser_context,
+                                              const GURL& effective_url);
+
  protected:
   friend class BrowsingInstance;
   friend class SiteInstance;