Enable the brightness row to be visible at all times

Update the visibility of the the brightness row to be visible at all
time for Chrome OS MD; the visibility stays as it is for non-MD.

TEST=Tray_brightness_unittests in ash_unittests

BUG=631809

Review-Url: https://codereview.chromium.org/2329333002
Cr-Commit-Position: refs/heads/master@{#417975}

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

@@ -47,6 +47,9 @@ 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 {
@@ -123,11 +126,15 @@ BrightnessView::BrightnessView(bool default_view, double initial_percent)
       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());
+    }
   }
 }
 
@@ -143,11 +150,13 @@ void BrightnessView::SetBrightnessPercent(double percent) {
 }
 
 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) {

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

@@ -39,14 +39,17 @@ class TrayBrightnessTest : public test::AshTestBase {
 };
 
 // Tests that when the default view is initially created, that its
-// BrightnessView is created not visible.
+// BrightnessView is created not visible for non MD and visible for MD.
 TEST_F(TrayBrightnessTest, CreateDefaultView) {
   std::unique_ptr<views::View> tray(CreateDefaultView());
-  EXPECT_FALSE(tray->visible());
+  if (ash::MaterialDesignController::IsSystemTrayMenuMaterial())
+    EXPECT_TRUE(tray->visible());
+  else
+    EXPECT_FALSE(tray->visible());
 }
 
 // Tests the construction of the default view while MaximizeMode is active.
-// The BrightnessView should be visible.
+// The BrightnessView should be visible for both modes non MD and MD.
 TEST_F(TrayBrightnessTest, CreateDefaultViewDuringMaximizeMode) {
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       true);
@@ -56,8 +59,9 @@ TEST_F(TrayBrightnessTest, CreateDefaultViewDuringMaximizeMode) {
       false);
 }
 
-// Tests that the enabling of MaximizeMode affects a previously created
-// BrightnessView, changing the visibility.
+// Tests that, when MD is not enabled, then the enabling of MaximizeMode
+// affects a previously created BrightnessView, changing the visibility; when MD
+// is enabled, then the BrightnessView is visible regardless of the mode change.
 TEST_F(TrayBrightnessTest, DefaultViewVisibilityChangesDuringMaximizeMode) {
   std::unique_ptr<views::View> tray(CreateDefaultView());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
@@ -65,18 +69,21 @@ TEST_F(TrayBrightnessTest, DefaultViewVisibilityChangesDuringMaximizeMode) {
   EXPECT_TRUE(tray->visible());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       false);
-  EXPECT_FALSE(tray->visible());
+  if (ash::MaterialDesignController::IsSystemTrayMenuMaterial())
+    EXPECT_TRUE(tray->visible());
+  else
+    EXPECT_FALSE(tray->visible());
 }
 
 // Tests that when the detailed view is initially created that its
-// BrightnessView is created as visible.
+// BrightnessView is created as visible for both MD and non MD modes.
 TEST_F(TrayBrightnessTest, CreateDetailedView) {
   std::unique_ptr<views::View> tray(CreateDetailedView());
   EXPECT_TRUE(tray->visible());
 }
 
 // Tests that when the detailed view is created during MaximizeMode that its
-// BrightnessView is visible.
+// BrightnessView is visible for both MD and non MD modes.
 TEST_F(TrayBrightnessTest, CreateDetailedViewDuringMaximizeMode) {
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(
       true);
@@ -87,7 +94,8 @@ TEST_F(TrayBrightnessTest, CreateDetailedViewDuringMaximizeMode) {
 }
 
 // Tests that the enabling of MaximizeMode has no affect on the visibility of a
-// previously created BrightnessView that belongs to a detailed view.
+// previously created BrightnessView that belongs to a detailed view for both MD
+// and non MD modes.
 TEST_F(TrayBrightnessTest, DetailedViewVisibilityChangesDuringMaximizeMode) {
   std::unique_ptr<views::View> tray(CreateDetailedView());
   WmShell::Get()->maximize_mode_controller()->EnableMaximizeModeWindowManager(