Do not activate system tray bubble by default

ash/common/system/chromeos/tray_caps_lock.cc

Index: ash/common/system/chromeos/tray_caps_lock.cc
diff --git a/ash/common/system/chromeos/tray_caps_lock.cc b/ash/common/system/chromeos/tray_caps_lock.cc
index 87e02896f41ada6df549757c0c0f49d53820b76d..81ba7493b2e6f5d035d7643378021d5af5654a4f 100644
--- a/ash/common/system/chromeos/tray_caps_lock.cc
+++ b/ash/common/system/chromeos/tray_caps_lock.cc
@@ -40,7 +40,9 @@ bool CapsLockIsEnabled() {
 class CapsLockDefaultView : public ActionableView {
  public:
   CapsLockDefaultView()
-      : text_label_(new views::Label), shortcut_label_(new views::Label) {
+      : ActionableView(nullptr),
+        text_label_(new views::Label),
+        shortcut_label_(new views::Label) {
     SetLayoutManager(new views::BoxLayout(views::BoxLayout::kHorizontal,
                                           kTrayPopupPaddingHorizontal, 0,
                                           kTrayPopupPaddingBetweenItems));