make NavigationGesture part of public content API and use it outside content

content/public/browser/navigation_handle.cc

Index: content/public/browser/navigation_handle.cc
diff --git a/content/public/browser/navigation_handle.cc b/content/public/browser/navigation_handle.cc
index 7a15413f719880ab0404a53bdd84db0f16887b1a..8d7a3ff5e284830abe5a1e24d35cd4b1dbe60da8 100644
--- a/content/public/browser/navigation_handle.cc
+++ b/content/public/browser/navigation_handle.cc
@@ -27,7 +27,7 @@ NavigationHandle::CreateNavigationHandleForTesting(
     RenderFrameHost* render_frame_host,
     bool committed,
     net::Error error,
-    bool has_user_gesture) {
+    NavigationGesture gesture) {
   std::unique_ptr<NavigationHandleImpl> handle_impl =
       NavigationHandleImpl::Create(
           url, static_cast<RenderFrameHostImpl*>(render_frame_host)
@@ -35,8 +35,7 @@ NavigationHandle::CreateNavigationHandleForTesting(
           true,   // is_renderer_initiated
           false,  // is_same_page
           false,  // is_srcdoc
-          base::TimeTicks::Now(), 0,
-          has_user_gesture ? NavigationGestureUser : NavigationGestureAuto,
+          base::TimeTicks::Now(), 0, gesture,
           false);  // started_from_context_menu
   handle_impl->set_render_frame_host(
       static_cast<RenderFrameHostImpl*>(render_frame_host));