Fix Volume slider is captured in screenshot done in touchview mode

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 979e3a197bf51a66dbd25c7795bd57f0adfe2872..3d63256749a8d228e2b74016f75bbdd192f39e18 100644
--- a/ash/common/system/tray/system_tray.cc
+++ b/ash/common/system/tray/system_tray.cc
@@ -42,6 +42,7 @@
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/layout/fill_layout.h"
 #include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
 
 #if defined(OS_CHROMEOS)
 #include "ash/common/system/chromeos/audio/tray_audio_chromeos.h"
@@ -277,7 +278,17 @@ void SystemTray::SetDetailedViewCloseDelay(int close_delay) {
     system_bubble_->bubble()->StartAutoCloseTimer(close_delay);
 }
 
-void SystemTray::HideDetailedView(SystemTrayItem* item) {
+void SystemTray::HideDetailedView(SystemTrayItem* item, bool hide_animation) {
+  if (!hide_animation) {
+    // In unittest, GetSystemBubble might return nullptr.
+    if (GetSystemBubble()) {
+      GetSystemBubble()
+          ->bubble_view()
+          ->GetWidget()
+          ->SetVisibilityAnimationTransition(

[Daniel Erat, 2016/07/28 22:20:40]

does this affect future transitions, or does a new view get created each time
the bubble is shown?

[Qiang(Joe) Xu, 2016/07/28 23:15:57]

Yes, systembubble is autoclosed everytime. So this should be fine. 

+              views::Widget::VisibilityTransition::ANIMATE_NONE);
+    }
+  }
   if (item != detailed_item_)
     return;
   DestroySystemBubble();