Stop using shell::GetInstance()->system_tray() in system tray items

ash/system/tray/system_tray_item.h

Index: ash/system/tray/system_tray_item.h
diff --git a/ash/system/tray/system_tray_item.h b/ash/system/tray/system_tray_item.h
index 6361529f8448798a6063310228fa3a620f136eb6..5366e78a174b1d18145ed1ba9465514a349486c6 100644
--- a/ash/system/tray/system_tray_item.h
+++ b/ash/system/tray/system_tray_item.h
@@ -39,8 +39,9 @@ class ASH_EXPORT SystemTrayItem {
 
   // Returns a view for the item to be displayed in the list. This view can be
   // displayed with a number of other tray items, so this should not be too
-  // big.
-  virtual views::View* CreateDefaultView(user::LoginStatus status);
+  // big. |bubble_width| is the current width of the bubble.
+  virtual views::View* CreateDefaultView(user::LoginStatus status,
+                                         int bubble_width);

[stevenjb, 2012/11/15 21:42:04]

This is a lot of changes for one use case, and seems like something we would
want for CreateDetailedView() also if we did this.

We already have a bunch of code in SystemTrayItem that calls
Shell::GetInstance()->system_tray(). This will be invalid soon because there may
be more than one system tray, so we will need to set a system_tray_ member in
each SystemTrayItem eventually anyway.

I propose that instead of this change, we pass |this| to each SystemTrayItem
constructor in SystemTray::CreateItems(). Then, any SystemTrayItem code that
needs the bubble width can call:

DCHECK(system_tray()->GetBubbleView());
int width = system_tray()->GetBubbleView()->GetPreferredSize().width();

Make sense?

[bartfab (slow), 2012/11/16 14:56:24]

Done. This is a much bigger refactor than I had been planning on doing :).

[stevenjb, 2012/11/16 17:46:55]

Yeah, sorry about that, but really appreciate it. 

 
   // Returns a detailed view for the item. This view is displayed standalone.
   virtual views::View* CreateDetailedView(user::LoginStatus status);
@@ -100,6 +101,13 @@ class ASH_EXPORT SystemTrayItem {
   // the launcher is in the auto-hide state. Default is true.
   virtual bool ShouldShowLauncher() const;
 
+  // For views displayed in a bubble, the width is normally determined by a
+  // fixed bubble with. If this returns true, the bubble width is adjusted when

[msw, 2012/11/15 21:08:48]

nit: s/with/width

+  // displaying this item's default view so that the view can be assigned at
+  // least its entire preferred size. Default is false.

[stevenjb, 2012/11/15 21:42:04]

This feels awkward. How about a GetMinWidth() that defaults to returning 0
(meaning no minimum)? Cases that would return 'true' here, would return
default_view_->GetPreferredSize().width(). Also, if the class needs LoginStatus
to determine this it should store it, instead of passing it here again.

[bartfab (slow), 2012/11/16 14:56:24]

Now that Tray*View can walk up the pointer chain all the way to the bubble, I
can make it explicitly modify the bubble width as needed by doing something like
this:

owner()->system_tray()->GetBubbleView()->SetWidth(x);

[stevenjb, 2012/11/16 17:46:55]

That sounds reasonable also.

+  virtual bool GuaranteeDefaultViewPreferredSize(
+      user::LoginStatus status) const;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(SystemTrayItem);
 };