Implement ProcessReusePolicy for SiteInstances

content/browser/site_instance_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
 #define CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 33 matching lines @@
   bool HasProcess() const override;
   RenderProcessHost* GetProcess() override;
   BrowserContext* GetBrowserContext() const override;
   const GURL& GetSiteURL() const override;
   scoped_refptr<SiteInstance> GetRelatedSiteInstance(const GURL& url) override;
   bool IsRelatedSiteInstance(const SiteInstance* instance) override;
   size_t GetRelatedActiveContentsCount() override;
   bool RequiresDedicatedProcess() override;
   bool IsDefaultSubframeSiteInstance() const override;
 
+  // The policy to apply when selecting a RenderProcessHost for the
+  // SiteInstance. Normal SiteInstances don't proactively reuse processes, but
+  // when over the limit, they reuse randomly, not based on site. In contrast,
+  // process-per-site and ServiceWorkers proactively join a process that already
+  // contains the site.
+  enum class ProcessReusePolicy {
+    // In this mode, all instances of the site will be hosted in the same
+    // RenderProcessHost.
+    PROCESS_PER_SITE,
+
+    // In this mode, subframes will be hosted in a designated RenderProcessHost.
+    USE_DEFAULT_SUBFRAME_PROCESS,
+
+    // By default, a new RenderProcessHost will be created unless the process
+    // limit has been reached. The RenderProcessHost reused will be chosen
+    // randomly and not based on the site.
+    DEFAULT,
+  };
+
+  void set_process_reuse_policy(ProcessReusePolicy policy) {
+    process_reuse_policy_ = policy;
+  }
+  ProcessReusePolicy process_reuse_policy() const {
+    return process_reuse_policy_;
+  }
+
   // Returns the SiteInstance, related to this one, that should be used
   // for subframes when an oopif is required, but a dedicated process is not.
   // This SiteInstance will be created if it doesn't already exist. There is
   // at most one of these per BrowsingInstance.
   scoped_refptr<SiteInstanceImpl> GetDefaultSubframeSiteInstance();
 
   // Set the web site that this SiteInstance is rendering pages for.
   // 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.
@@ skipping 30 matching lines @@
   // that, unlike active_frame_count, this does not count pending RFHs.
   void IncrementRelatedActiveContentsCount();
 
   // Decrease the number of active WebContentses using this SiteInstance. Note
   // that, unlike active_frame_count, this does not count pending RFHs.
   void DecrementRelatedActiveContentsCount();
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
-  // Sets the global factory used to create new RenderProcessHosts.  It may be
-  // NULL, in which case the default RenderProcessHost will be created (this is
-  // the behavior if you don't call this function).  The factory must be set
-  // back to NULL before it's destroyed; ownership is not transferred.
-  static void set_render_process_host_factory(
-      const RenderProcessHostFactory* rph_factory);
-
   // Get the effective URL for the given actual URL.  This allows the
   // ContentBrowserClient to override the SiteInstance's site for certain URLs.
   // For example, Chrome uses this to replace hosted app URLs with extension
   // hosts.
   // Only public so that we can make a consistent process swap decision in
   // RenderFrameHostManager.
   static GURL GetEffectiveURL(BrowserContext* browser_context,
                               const GURL& url);
 
   // Returns true if pages loaded from |url| ought to be handled only by a
@@ skipping 21 matching lines @@
                            int exit_code) override;
 
   // Used to restrict a process' origin access rights.
   void LockToOrigin();
 
   // This gets the render process to use for default subframe site instances.
   RenderProcessHost* GetDefaultSubframeProcessHost(
       BrowserContext* browser_context,
       bool is_for_guests_only);
 
-  void set_is_default_subframe_site_instance() {
-    is_default_subframe_site_instance_ = true;
-  }
-
   // An object used to construct RenderProcessHosts.
   static const RenderProcessHostFactory* g_render_process_host_factory_;
 
   // The next available SiteInstance ID.
   static int32_t next_site_instance_id_;
 
   // A unique ID for this SiteInstance.
   int32_t id_;
 
   // The number of active frames in this SiteInstance.
   size_t active_frame_count_;
 
   // BrowsingInstance to which this SiteInstance belongs.
   scoped_refptr<BrowsingInstance> browsing_instance_;
 
   // Current RenderProcessHost that is rendering pages for this SiteInstance.
   // This pointer will only change once the RenderProcessHost is destructed.  It
   // will still remain the same even if the process crashes, since in that
   // scenario the RenderProcessHost remains the same.
   RenderProcessHost* process_;
 
   // The web site that this SiteInstance is rendering pages for.
   GURL site_;
 
   // Whether SetSite has been called.
   bool has_site_;
 
-  // Whether this SiteInstance is the default subframe SiteInstance for its
-  // BrowsingInstance. Only one SiteInstance per BrowsingInstance can have this
-  // be true.
-  bool is_default_subframe_site_instance_;
+  // The ProcessReusePolicy to use when creating a RenderProcessHost for this
+  // SiteInstance.
+  ProcessReusePolicy process_reuse_policy_;
 
   base::ObserverList<Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteInstanceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_