PlzNavigate: implement REUSE_COMMITTED_OR_PENDING_SITE for redirects

content/browser/frame_host/navigation_handle_impl.h

Index: content/browser/frame_host/navigation_handle_impl.h
diff --git a/content/browser/frame_host/navigation_handle_impl.h b/content/browser/frame_host/navigation_handle_impl.h
index f98451b72daee71b3a85188a0ab677595d327159..2df307fc898dfa87fadc86c4157a544c153ec5c5 100644
--- a/content/browser/frame_host/navigation_handle_impl.h
+++ b/content/browser/frame_host/navigation_handle_impl.h
@@ -284,6 +284,7 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
       bool new_is_external_protocol,
       scoped_refptr<net::HttpResponseHeaders> response_headers,
       net::HttpResponseInfo::ConnectionInfo connection_info,
+      RenderProcessHost* new_expected_render_process_host,

[Charlie Reis, 2017/06/27 04:24:53]

Maybe new_expected_process or post_redirect_process (here and below)?

We should also include a comment about this above, and whether it's null in some
cases.

[clamy, 2017/06/27 15:23:05]

Done.

       const ThrottleChecksFinishedCallback& callback);
 
   // Called when the URLRequest has delivered response headers and metadata.
@@ -430,9 +431,11 @@ class CONTENT_EXPORT NavigationHandleImpl : public NavigationHandle {
 
   // Updates the destination site URL for this navigation. This is called on
   // redirects.
-  // PlzNavigate: When redirected cross-site, the speculative RenderProcessHost
-  // will stop expecting this navigation to commit.
-  void UpdateSiteURL();
+  // PlzNavigate: |new_expected_render_process_host_id| is the id of the
+  // renderer process that should handle the navigation following the redirect
+  // if it can be handled by an existing RenderProcessHost. Otherwise, it should
+  // be ChildProcessHost::kInvalidUniqueID.

[Charlie Reis, 2017/06/27 04:24:53]

This comment is talking about IDs, but we pass a RenderProcessHost* below.

[clamy, 2017/06/27 15:23:05]

Done.

+  void UpdateSiteURL(RenderProcessHost* new_expected_render_process_host);
 
   // See NavigationHandle for a description of those member variables.
   GURL url_;