[ash-md] Hides frame headers in overview mode not using a mask

ash/frame/custom_frame_view_ash.cc

Index: ash/frame/custom_frame_view_ash.cc
diff --git a/ash/frame/custom_frame_view_ash.cc b/ash/frame/custom_frame_view_ash.cc
index c188b9949faaac4636be2d04230c7b683a1a6945..69f83b469684b0e8cbd03d5bb79040b169a9c6ce 100644
--- a/ash/frame/custom_frame_view_ash.cc
+++ b/ash/frame/custom_frame_view_ash.cc
@@ -9,6 +9,7 @@
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/ash_switches.h"
+#include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shell_observer.h"
 #include "ash/common/wm/window_state.h"
@@ -167,6 +168,8 @@ class CustomFrameViewAsh::HeaderView
   // ShellObserver:
   void OnMaximizeModeStarted() override;
   void OnMaximizeModeEnded() override;
+  void OnOverviewModeStarting() override;
+  void OnOverviewModeEnded() override;
 
   FrameCaptionButtonContainerView* caption_button_container() {
     return caption_button_container_;
@@ -320,6 +323,16 @@ void CustomFrameViewAsh::HeaderView::OnMaximizeModeEnded() {
   parent()->Layout();
 }
 
+void CustomFrameViewAsh::HeaderView::OnOverviewModeStarting() {
+  if (ash::MaterialDesignController::IsOverviewMaterial())
+    SetVisible(false);
+}
+
+void CustomFrameViewAsh::HeaderView::OnOverviewModeEnded() {
+  if (ash::MaterialDesignController::IsOverviewMaterial())
+    SetVisible(true);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // CustomFrameViewAsh::HeaderView,
 //   ImmersiveFullscreenController::Delegate overrides: