Fix Chrome crashes on calling OnTrayVisibilityChange

ash/common/system/chromeos/palette/palette_tray.cc

Index: ash/common/system/chromeos/palette/palette_tray.cc
diff --git a/ash/common/system/chromeos/palette/palette_tray.cc b/ash/common/system/chromeos/palette/palette_tray.cc
index 2cfc5b8af776a8d412eed64d2739ccf4990423d4..179be69fd967c0b5e0bbcde240bccb65415f2f16 100644
--- a/ash/common/system/chromeos/palette/palette_tray.cc
+++ b/ash/common/system/chromeos/palette/palette_tray.cc
@@ -204,13 +204,6 @@ PaletteTray::PaletteTray(WmShelf* wm_shelf)
         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() {
@@ -413,6 +406,15 @@ void PaletteTray::AnchorUpdated() {
     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.