Set user_gesture bit at NavigationHandle creation time.

content/public/browser/navigation_handle.h

Index: content/public/browser/navigation_handle.h
diff --git a/content/public/browser/navigation_handle.h b/content/public/browser/navigation_handle.h
index f2506c82dce30a5df29d0599180cd8268f09ae2a..49149a14ed2f71e1b600a8d22be6905cb2f74b90 100644
--- a/content/public/browser/navigation_handle.h
+++ b/content/public/browser/navigation_handle.h
@@ -196,7 +196,8 @@ class CONTENT_EXPORT NavigationHandle {
       const GURL& url,
       RenderFrameHost* render_frame_host,
       bool committed = false,
-      net::Error error = net::OK);
+      net::Error error = net::OK,
+      bool has_user_gesture = false);

[clamy, 2016/11/21 16:50:46]

Should this take a NavigationGesture as well?

[Bryan McQuade, 2016/11/22 14:13:03]

NavigationGesture isn't currently part of the public content API, so I'm
inclined to defer that until its own subsequent change, since that'll involve
updating #includes of navigation_gesture.h. I did prototype moving
NavigationGesture to the public API in
https://codereview.chromium.org/2524763002 and we can go forward with that if
you like, but also happy to defer that decision to a separate change.

 
   // Registers a NavigationThrottle for tests. The throttle can
   // modify the request, pause the request or cancel the request. This will
@@ -212,7 +213,6 @@ class CONTENT_EXPORT NavigationHandle {
   virtual NavigationThrottle::ThrottleCheckResult
   CallWillStartRequestForTesting(bool is_post,
                                  const Referrer& sanitized_referrer,
-                                 bool has_user_gesture,
                                  ui::PageTransition transition,
                                  bool is_external_protocol) = 0;