Fix Chrome crashes on calling OnTrayVisibilityChange

ash/common/system/chromeos/palette/palette_tray.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/system/chromeos/palette/palette_tray.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ skipping 186 matching lines @@
   SetIconBorderForShelfAlignment();
   tray_container()->AddChildView(icon_);
 
   WmShell::Get()->AddShellObserver(this);
   WmShell::Get()->GetSessionStateDelegate()->AddSessionStateObserver(this);
   if (WmShell::Get()->palette_delegate()) {
     WmShell::Get()->palette_delegate()->SetStylusStateChangedCallback(
         base::Bind(&PaletteTray::OnStylusStateChanged,
                    weak_factory_.GetWeakPtr()));
   }
-
-  // OnPaletteEnabledPrefChanged will get called with the initial pref value,
-  // which will take care of showing the palette.
-  palette_enabled_subscription_ =
-      WmShell::Get()->palette_delegate()->AddPaletteEnableListener(
-          base::Bind(&PaletteTray::OnPaletteEnabledPrefChanged,
-                     weak_factory_.GetWeakPtr()));
 }
 
 PaletteTray::~PaletteTray() {
   if (bubble_)
     bubble_->bubble_view()->reset_delegate();
 
   WmShell::Get()->RemoveShellObserver(this);
   WmShell::Get()->GetSessionStateDelegate()->RemoveSessionStateObserver(this);
 }
 
@@ skipping 182 matching lines @@
 
   TrayBackgroundView::SetShelfAlignment(alignment);
   SetIconBorderForShelfAlignment();
 }
 
 void PaletteTray::AnchorUpdated() {
   if (bubble_)
     bubble_->bubble_view()->UpdateBubble();
 }
 
+void PaletteTray::Initialize() {
+  // OnPaletteEnabledPrefChanged will get called with the initial pref value,
+  // which will take care of showing the palette.
+  palette_enabled_subscription_ =
+      WmShell::Get()->palette_delegate()->AddPaletteEnableListener(
+          base::Bind(&PaletteTray::OnPaletteEnabledPrefChanged,
+                     weak_factory_.GetWeakPtr()));
+}
+
 void PaletteTray::SetIconBorderForShelfAlignment() {
   // TODO(tdanderson): Ensure PaletteTray follows material design specs. See
   // crbug.com/630464.
   if (IsHorizontalAlignment(shelf_alignment())) {
     icon_->SetBorder(views::CreateEmptyBorder(gfx::Insets(
         kHorizontalShelfVerticalPadding, kHorizontalShelfHorizontalPadding)));
   } else {
     icon_->SetBorder(views::CreateEmptyBorder(gfx::Insets(
         kVerticalShelfVerticalPadding, kVerticalShelfHorizontalPadding)));
   }
@@ skipping 38 matching lines @@
   } else {
     UpdateIconVisibility();
   }
 }
 
 void PaletteTray::UpdateIconVisibility() {
   SetVisible(is_palette_enabled_ && IsInUserSession());
 }
 
 }  // namespace ash