Allow Uber Tray popup pointing to the related tray item view.

ash/system/tray/system_tray_bubble.h

Index: ash/system/tray/system_tray_bubble.h
diff --git a/ash/system/tray/system_tray_bubble.h b/ash/system/tray/system_tray_bubble.h
index a29e7488342e8db5a0051d04595d986bb16eb7ec..d31cc468df90dc755980402ae3b34913c166270d 100644
--- a/ash/system/tray/system_tray_bubble.h
+++ b/ash/system/tray/system_tray_bubble.h
@@ -70,6 +70,16 @@ class SystemTrayBubble : public base::MessagePumpObserver,
     ANCHOR_TYPE_BUBBLE
   };
 
+  struct InitParams {
+    InitParams(AnchorType anchor_type);
+
+    views::View* anchor;
+    AnchorType anchor_type;
+    bool can_activate;
+    ash::user::LoginStatus login_status;
+    int arrow_offset;
+  };
+
   SystemTrayBubble(ash::SystemTray* tray,
                    const std::vector<ash::SystemTrayItem*>& items,
                    BubbleType bubble_type);
@@ -77,10 +87,7 @@ class SystemTrayBubble : public base::MessagePumpObserver,
 
   // Creates |bubble_view_| and a child views for each member of |items_|.
   // Also creates |bubble_widget_| and sets up animations.
-  void InitView(views::View* anchor,
-                AnchorType anchor_type,
-                bool can_activate,
-                ash::user::LoginStatus login_status);
+  void InitView(const InitParams& init_params);
 
   gfx::Rect GetAnchorRect() const;