Layout the wide frame when exiting immersive fullscreen

Since the wide frame doesn't have the content,
relayout doesn't happen automatically.

Bug: 882080
Test: manual
Change-Id: Ia24a4d71a3f7b74834cc423fbdf87d096231b1f2
Reviewed-on: https://chromium-review.googlesource.com/1214687Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589758}

ash/frame/wide_frame_view.cc

@@ -178,6 +178,7 @@ void WideFrameView::OnImmersiveFullscreenExited() {
   header_view_->OnImmersiveFullscreenExited();
   if (target_)
     GetTargetHeaderView()->OnImmersiveFullscreenExited();
+  Layout();
 }
 
 void WideFrameView::SetVisibleFraction(double visible_fraction) {