Enable spare RenderProcessHost to be preinitialized.

content/browser/renderer_host/render_process_host_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_RENDERER_HOST_RENDER_PROCESS_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_PROCESS_HOST_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 96 matching lines @@
 // because all the IPCs from the RenderViews (renderer) will only ever be able
 // to access the partition they are assigned to.
 class CONTENT_EXPORT RenderProcessHostImpl
     : public RenderProcessHost,
       public ChildProcessLauncher::Client,
       public ui::GpuSwitchingObserver,
       public NON_EXPORTED_BASE(mojom::RouteProvider),
       public NON_EXPORTED_BASE(mojom::AssociatedInterfaceProvider),
       public NON_EXPORTED_BASE(mojom::RendererHost) {
  public:
-  RenderProcessHostImpl(BrowserContext* browser_context,
-                        StoragePartitionImpl* storage_partition_impl,
-                        bool is_for_guests_only);
+  static RenderProcessHost* CreateRenderProcessHost(
+      BrowserContext* browser_context,
+      StoragePartitionImpl* storage_partition_impl,
+      bool is_for_guests_only);
+
   ~RenderProcessHostImpl() override;
 
   // RenderProcessHost implementation (public portion).
   bool Init() override;
   void EnableSendQueue() override;
   int GetNextRoutingID() override;
   void AddRoute(int32_t routing_id, IPC::Listener* listener) override;
   void RemoveRoute(int32_t routing_id) override;
   void AddObserver(RenderProcessHostObserver* observer) override;
   void RemoveObserver(RenderProcessHostObserver* observer) override;
@@ skipping 224 matching lines @@
   // started to swap these in, so the renderer process should not exit if
   // this count is non-zero.
   int32_t pending_views_;
 
  private:
   friend class ChildProcessLauncherBrowserTest_ChildSpawnFail_Test;
   friend class VisitRelayingRenderProcessHost;
   class ConnectionFilterController;
   class ConnectionFilterImpl;
 
+  // Use CreateRenderProcessHostImpl() instead.
+  RenderProcessHostImpl(BrowserContext* browser_context,
+                        StoragePartitionImpl* storage_partition_impl,
+                        bool is_for_guests_only);
+
   // Initializes a new IPC::ChannelProxy in |channel_|, which will be connected
   // to the next child process launched for this host, if any.
   void InitializeChannelProxy();
 
   // Resets |channel_|, removing it from the attachment broker if necessary.
   // Always call this in lieu of directly resetting |channel_|.
   void ResetChannelProxy();
 
   // Creates and adds the IO thread message filters.
   void CreateMessageFilters();
@@ skipping 332 matching lines @@
   FrameSinkProviderImpl frame_sink_provider_;
 
   base::WeakPtrFactory<RenderProcessHostImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderProcessHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_PROCESS_HOST_IMPL_H_