Support Service Worker NavigationPreload with PlzNavigate.

content/public/browser/render_process_host.h

Index: content/public/browser/render_process_host.h
diff --git a/content/public/browser/render_process_host.h b/content/public/browser/render_process_host.h
index b2b7df69039177c494fc9f48df07cbd05bc2cf46..c2767125caccc66217595fadfd6b8954d61cf70d 100644
--- a/content/public/browser/render_process_host.h
+++ b/content/public/browser/render_process_host.h
@@ -10,6 +10,7 @@
 
 #include <list>
 
+#include "base/callback_forward.h"
 #include "base/id_map.h"
 #include "base/memory/ptr_util.h"
 #include "base/process/kill.h"
@@ -18,6 +19,7 @@
 #include "content/common/content_export.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_sender.h"
+#include "mojo/public/cpp/bindings/interface_request.h"
 #include "ui/gfx/native_widget_types.h"
 
 class GURL;
@@ -47,6 +49,7 @@ struct GlobalRequestID;
 
 namespace mojom {
 class Renderer;
+class URLLoaderFactory;
 }
 
 // Interface that represents the browser side of the browser <-> renderer
@@ -57,6 +60,8 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
                                          public base::SupportsUserData {
  public:
   typedef IDMap<RenderProcessHost>::iterator iterator;
+  using MojoURLLoaderFactoryGetter =
+      base::Callback<void(mojo::InterfaceRequest<mojom::URLLoaderFactory>)>;
 
   // Details for RENDERER_PROCESS_CLOSED notifications.
   struct RendererClosedDetails {
@@ -331,6 +336,10 @@ class CONTENT_EXPORT RenderProcessHost : public IPC::Sender,
   // MockRenderProcessHost usage in tests.
   virtual mojom::Renderer* GetRendererInterface() = 0;
 
+  // Creates a MojoURLLoaderFactoryGetter associated with the process. This is
+  // used for fetching navigation preload request.

[falken, 2016/10/27 02:07:49]

I think we can remove the second sentence, since the URL loader factory is
potentially useful for purposes other than navigation preload (I think). If it
could only possible be used for navigation preload, the function name should be
something like CreateURLLoaderFactoryGetterForNavigationPreload.

Ideally we'd avoid a new function on RPH and just have the caller bind the
function itself using RenderProcessHostImpl::CreateURLLoaderFactory, but I see
there is no GetWeakPtr() function and adding it might be controversial.

Also, does CreateURLLoaderFactoryGetter() have to be on the public interface or
can it just be on RenderProcessHostInstance?

[horo, 2016/10/27 02:20:27]

done.
Are you saying about RenderProcessHostImpl?
We have to have this method in RenderProcessHost, because some unittests
(NavigatorTestWithBrowserSideNavigation) are using MockRenderProcessHost , not
RenderProcessHostImpl.

[falken, 2016/10/27 02:27:56]

Yes, Impl. Acknowledged.

+  virtual MojoURLLoaderFactoryGetter CreateURLLoaderFactoryGetter() = 0;
+
   // Returns the current number of active views in this process.  Excludes
   // any RenderViewHosts that are swapped out.
   size_t GetActiveViewCount();