cleanup: Remove the system tray bubble crash investigation CHECK

ash/common/system/tray/system_tray.cc

Index: ash/common/system/tray/system_tray.cc
diff --git a/ash/common/system/tray/system_tray.cc b/ash/common/system/tray/system_tray.cc
index b471a79cd70638c73d35de43c0c5c0d0eba675d1..7a79b811ccb46fdbc6a621b78dabef0f35b6cd7f 100644
--- a/ash/common/system/tray/system_tray.cc
+++ b/ash/common/system/tray/system_tray.cc
@@ -421,7 +421,6 @@ bool SystemTray::IsSystemBubbleVisible() const {
 bool SystemTray::CloseSystemBubble() const {
   if (!system_bubble_)
     return false;
-  CHECK(!activating_);
   system_bubble_->bubble()->Close();
   return true;
 }
@@ -667,12 +666,7 @@ void SystemTray::CloseBubble(const ui::KeyEvent& key_event) {
 void SystemTray::ActivateAndStartNavigation(const ui::KeyEvent& key_event) {
   if (!system_bubble_)
     return;
-  activating_ = true;
   ActivateBubble();
-  activating_ = false;
-  // TODO(oshima): This is to troubleshoot the issue crbug.com/651242. Remove
-  // once the root cause is fixed.
-  CHECK(system_bubble_) << " the bubble was deleted while activaing it";
 
   views::Widget* widget = GetSystemBubble()->bubble_view()->GetWidget();
   widget->GetFocusManager()->OnKeyEvent(key_event);
@@ -720,7 +714,6 @@ bool SystemTray::PerformAction(const ui::Event& event) {
 }
 
 void SystemTray::CloseSystemBubbleAndDeactivateSystemTray() {
-  CHECK(!activating_);
   activation_observer_.reset();
   key_event_watcher_.reset();
   system_bubble_.reset();