Don't create separate SiteInstances for pages from the same domain and scheme...

chrome/browser/site_instance.h

 // Copyright (c) 2006-2008 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.
 
 #ifndef CHROME_BROWSER_SITE_INSTANCE_H__
 #define CHROME_BROWSER_SITE_INSTANCE_H__
 
 #include "chrome/browser/browsing_instance.h"
 #include "chrome/browser/render_process_host.h"
 #include "googleurl/src/gurl.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 // SiteInstance class
 //
 // A SiteInstance is a data structure that is associated with all pages in a
 // given instance of a web site.  Here, a web site is identified by its
-// registered domain name, scheme, and port.  An instance includes all pages
+// registered domain name and scheme.  An instance includes all pages
 // that are connected (i.e., either a user or a script navigated from one
 // to the other).  We represent instances using the BrowsingInstance class.
 //
 // In --process-per-tab, one SiteInstance is created for each tab (i.e., in the
 // WebContents constructor), unless the tab is created by script (i.e., in
 // WebContents::CreateNewView).  This corresponds to one process per
 // BrowsingInstance.
 //
 // In process-per-site-instance (the current default process model),
 // SiteInstances are created (1) when the user manually creates a new tab
@@ skipping 34 matching lines @@
       max_page_id_ = page_id;
   }
   int32 max_page_id() const { return max_page_id_; }
 
   // Returns the current process being used to render pages in this
   // SiteInstance.  If the process has crashed or otherwise gone away, then
   // this method will create a new process and update our host ID accordingly.
   RenderProcessHost* GetProcess();
 
   // Set / Get the web site that this SiteInstance is rendering pages for.
-  // This includes the scheme, registered domain, and port.  If the URL does
-  // not have a valid registered domain, then the full hostname is stored.
+  // This includes the scheme and registered domain, but not the port.  If the
+  // URL does not have a valid registered domain, then the full hostname is
+  // stored.
   void SetSite(const GURL& url);
   const GURL& site() const { return site_; }
   bool has_site() const { return has_site_; }
 
   // Returns whether there is currently a related SiteInstance (registered with
   // BrowsingInstance) for the site of the given url.  If so, we should try to
   // avoid dedicating an unused SiteInstance to it (e.g., in a new tab).
   bool HasRelatedSiteInstance(const GURL& url);
 
   // Gets a SiteInstance for the given URL that shares the current
   // BrowsingInstance, creating a new SiteInstance if necessary.  This ensures
   // that a BrowsingInstance only has one SiteInstance per site, so that pages
   // in a BrowsingInstance have the ability to script each other.  Callers
   // should ensure that this SiteInstance becomes ref counted, by storing it in
   // a scoped_refptr.  (By having this method, we can hide the BrowsingInstance
   // class from the rest of the codebase.)
   // TODO(creis): This may be an argument to build a pass_refptr<T> class, as
   // Darin suggests.
   SiteInstance* GetRelatedSiteInstance(const GURL& url);
 
   // Factory method to create a new SiteInstance.  This will create a new
   // new BrowsingInstance, so it should only be used when creating a new tab
   // from scratch (or similar circumstances).  Callers should ensure that
   // this SiteInstance becomes ref counted, by storing it in a scoped_refptr.
   // TODO(creis): This may be an argument to build a pass_refptr<T> class, as
   // Darin suggests.
   static SiteInstance* CreateSiteInstance(Profile* profile);
 
-  // Returns the site for the given URL, which includes only the scheme,
-  // registered domain, and port.  Returns an empty GURL if the URL has no
-  // host.
+  // Returns the site for the given URL, which includes only the scheme and
+  // registered domain.  Returns an empty GURL if the URL has no host.
   static GURL GetSiteForURL(const GURL& url);
 
   // Return whether both URLs are part of the same web site, for the purpose of
   // assigning them to processes accordingly.  The decision is currently based
   // on the registered domain of the URLs (google.com, bbc.co.uk), as well as
-  // the scheme (https, http) and port.  This ensures that two pages will be in
+  // the scheme (https, http).  This ensures that two pages will be in
   // the same process if they can communicate with other via JavaScript.
   // (e.g., docs.google.com and mail.google.com have DOM access to each other
   // if they both set their document.domain properties to google.com.)
   static bool IsSameWebSite(const GURL& url1, const GURL& url2);
 
  protected:
   friend class BrowsingInstance;
 
   // Create a new SiteInstance.  Protected to give access to BrowsingInstance
   // and tests; most callers should use CreateSiteInstance or
@@ skipping 25 matching lines @@
   GURL site_;
 
   // Whether SetSite has been called.
   bool has_site_;
 
   DISALLOW_EVIL_CONSTRUCTORS(SiteInstance);
 };
 
 #endif  //  CHROME_BROWSER_SITE_INSTANCE_H__