Ash Tray: Fix crash when toggling mirror mode display.

The DictationButtonTray is updating its visibility in the constructor, which
causes a crash now that we have more complicated visibility logic. Instead move
the visibility update to the Initialize() function.

TEST=manually verified on device
BUG=1036052

Change-Id: I887a47ac2a655994b99d438df1b644d8fe75fd98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1976857Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Tim Song <tengs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#726967}

ash/system/accessibility/dictation_button_tray.cc

@@ -23,8 +23,6 @@ namespace ash {
 
 DictationButtonTray::DictationButtonTray(Shelf* shelf)
     : TrayBackgroundView(shelf), icon_(new views::ImageView()) {
-  UpdateVisibility();
-
   off_image_ = gfx::CreateVectorIcon(kDictationOffNewuiIcon,
                                      ShelfConfig::Get()->shelf_icon_color());
   on_image_ = gfx::CreateVectorIcon(kDictationOnNewuiIcon,
@@ -54,6 +52,11 @@ bool DictationButtonTray::PerformAction(const ui::Event& event) {
   return true;
 }
 
+void DictationButtonTray::Initialize() {
+  TrayBackgroundView::Initialize();
+  UpdateVisibility();
+}
+
 void DictationButtonTray::ClickedOutsideBubble() {}
 
 void DictationButtonTray::OnDictationStarted() {

ash/system/accessibility/dictation_button_tray.h

@@ -42,6 +42,7 @@ class ASH_EXPORT DictationButtonTray : public TrayBackgroundView,
   void OnAccessibilityStatusChanged() override;
 
   // TrayBackgroundView:
+  void Initialize() override;
   void ClickedOutsideBubble() override;
   base::string16 GetAccessibleNameForTray() override;
   void HideBubbleWithView(const TrayBubbleView* bubble_view) override;

ash/system/tray/tray_background_view.cc

@@ -516,6 +516,9 @@ bool TrayBackgroundView::GetEffectiveVisibility() {
   if (!visible_preferred_)
     return false;
 
+  if (!GetWidget())
+    return false;
+
   // When the status area is collapsed, the effective visibility of the view is
   // determined by |show_when_collapsed_|.
   StatusAreaWidget::CollapseState collapse_state =