[ash-md] Erases the pre-MD code path for Overview Mode

ash/common/frame/header_view.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/common/frame/header_view.h"
 
 #include "ash/common/frame/caption_buttons/frame_caption_button_container_view.h"
 #include "ash/common/frame/default_header_painter.h"
-#include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/wm_lookup.h"
 #include "ash/common/wm_shell.h"
 #include "ui/gfx/canvas.h"
 #include "ui/views/controls/image_view.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
 
 HeaderView::HeaderView(views::Widget* target_widget)
@@ skipping 107 matching lines @@
   // size changes.
   if (child != caption_button_container_)
     return;
   parent()->Layout();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // HeaderView, ShellObserver overrides:
 
 void HeaderView::OnOverviewModeStarting() {
-  if (MaterialDesignController::IsOverviewMaterial())
-    caption_button_container_->SetVisible(false);
+  caption_button_container_->SetVisible(false);
 }
 
 void HeaderView::OnOverviewModeEnded() {
-  if (MaterialDesignController::IsOverviewMaterial())
-    caption_button_container_->SetVisible(true);
+  caption_button_container_->SetVisible(true);
 }
 
 void HeaderView::OnMaximizeModeStarted() {
   caption_button_container_->UpdateSizeButtonVisibility();
   parent()->Layout();
 }
 
 void HeaderView::OnMaximizeModeEnded() {
   caption_button_container_->UpdateSizeButtonVisibility();
   parent()->Layout();
@@ skipping 38 matching lines @@
   gfx::Rect visible_bounds(GetVisibleBounds());
   gfx::Point visible_origin_in_screen(visible_bounds.origin());
   views::View::ConvertPointToScreen(this, &visible_origin_in_screen);
   std::vector<gfx::Rect> bounds_in_screen;
   bounds_in_screen.push_back(
       gfx::Rect(visible_origin_in_screen, visible_bounds.size()));
   return bounds_in_screen;
 }
 
 }  // namespace ash