Enable spare RenderProcessHost to be preinitialized.

content/browser/renderer_host/render_process_host_impl.h

Index: content/browser/renderer_host/render_process_host_impl.h
diff --git a/content/browser/renderer_host/render_process_host_impl.h b/content/browser/renderer_host/render_process_host_impl.h
index 96900941e917bf964a13293930b129bb36f9ab78..e2f1ea8d8029e790eac8d83e2064815c1c7f2a87 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -114,9 +114,11 @@ class CONTENT_EXPORT RenderProcessHostImpl
       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).
@@ -335,6 +337,8 @@ class CONTENT_EXPORT RenderProcessHostImpl
       RenderProcessHost* render_process_host,
       const GURL& site_url);
 
+  static void OnStorageParitionShutdown(StoragePartition* partition);
+
  protected:
   // A proxy for our IPC::Channel that lives on the IO thread.
   std::unique_ptr<IPC::ChannelProxy> channel_;
@@ -361,6 +365,12 @@ class CONTENT_EXPORT RenderProcessHostImpl
   class ConnectionFilterController;
   class ConnectionFilterImpl;
 
+  // Use CreateRenderProcessHostImpl() instead of calling this constructor

[falken, 2017/06/15 06:46:49]

typo? CreateRenderProcessHost()

[mattcary, 2017/06/15 08:30:39]

Done.

+  // directly.
+  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();