[Chrome OS MD] Enable the brightness row to be visible at all times

ash/common/system/chromeos/brightness/tray_brightness.cc

 // Copyright 2013 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/system/chromeos/brightness/tray_brightness.h"
 
 #include <algorithm>
 
 #include "ash/common/ash_constants.h"
 #include "ash/common/material_design/material_design_controller.h"
@@ skipping 29 matching lines @@
 namespace {
 
 // We don't let the screen brightness go lower than this when it's being
 // adjusted via the slider.  Otherwise, if the user doesn't know about the
 // brightness keys, they may turn the backlight off and not know how to turn it
 // back on.
 const double kMinBrightnessPercent = 5.0;
 
 }  // namespace
 
+// TODO(yiyix|tdanderson): Once Chrome OS material design is enabled by default,
+// BrightnessView does not need to be a ShellObserver to observe touch view mode
+// changes. See crbug.com/614453.
 class BrightnessView : public ShellObserver,
                        public views::View,
                        public views::SliderListener {
  public:
   BrightnessView(bool default_view, double initial_percent);
   ~BrightnessView() override;
 
   bool is_default_view() const { return is_default_view_; }
 
   // |percent| is in the range [0.0, 100.0].
@@ skipping 56 matching lines @@
   if (ash::MaterialDesignController::IsSystemTrayMenuMaterial()) {
     slider_->SetBorder(views::Border::CreateEmptyBorder(
         gfx::Insets(0, kTrayPopupSliderPaddingMD) + slider_->GetInsets()));
   }
   slider_->set_focus_border_color(kFocusBorderColor);
   slider_->SetValue(static_cast<float>(initial_percent / 100.0));
   slider_->SetAccessibleName(
       rb.GetLocalizedString(IDS_ASH_STATUS_TRAY_BRIGHTNESS));
   AddChildView(slider_);
 
-  if (is_default_view_) {
-    WmShell::Get()->AddShellObserver(this);
-    SetVisible(WmShell::Get()
-                   ->maximize_mode_controller()
-                   ->IsMaximizeModeWindowManagerEnabled());
+  if (MaterialDesignController::IsSystemTrayMenuMaterial()) {
+    SetVisible(true);
+  } else {
+    if (is_default_view_) {
+      WmShell::Get()->AddShellObserver(this);
+      SetVisible(WmShell::Get()
+                     ->maximize_mode_controller()
+                     ->IsMaximizeModeWindowManagerEnabled());
+    }
   }
 }
 
 BrightnessView::~BrightnessView() {
   if (is_default_view_)
     WmShell::Get()->RemoveShellObserver(this);
 }
 
 void BrightnessView::SetBrightnessPercent(double percent) {
   last_percent_ = percent;
   if (!dragging_)
     slider_->SetValue(static_cast<float>(percent / 100.0));
 }
 
 void BrightnessView::OnMaximizeModeStarted() {
-  SetVisible(true);
+  if (!MaterialDesignController::IsSystemTrayMenuMaterial())
+    SetVisible(true);
 }
 
 void BrightnessView::OnMaximizeModeEnded() {
-  SetVisible(false);
+  if (!MaterialDesignController::IsSystemTrayMenuMaterial())
+    SetVisible(false);
 }
 
 void BrightnessView::OnBoundsChanged(const gfx::Rect& old_bounds) {
   int w = width() - slider_->x();
   slider_->SetSize(gfx::Size(w, slider_->height()));
 }
 
 void BrightnessView::SliderValueChanged(views::Slider* sender,
                                         float value,
                                         float old_value,
@@ skipping 121 matching lines @@
   if (!display::Display::HasInternalDisplay())
     return;
 
   if (brightness_view_)
     SetDetailedViewCloseDelay(kTrayPopupAutoCloseDelayInSeconds);
   else
     PopupDetailedView(kTrayPopupAutoCloseDelayInSeconds, false);
 }
 
 }  // namespace ash