Add GetMinimumSize() for Borders, and make LabelButton auto-size to at least as

ash/wm/caption_buttons/maximize_bubble_controller_bubble.cc

Index: ash/wm/caption_buttons/maximize_bubble_controller_bubble.cc
===================================================================
--- ash/wm/caption_buttons/maximize_bubble_controller_bubble.cc	(revision 236640)
+++ ash/wm/caption_buttons/maximize_bubble_controller_bubble.cc	(working copy)
@@ -147,6 +147,7 @@
   virtual gfx::Rect GetBounds(const gfx::Rect& position_relative_to,
                               const gfx::Size& contents_size) const OVERRIDE;
   virtual void Paint(const views::View& view, gfx::Canvas* canvas) OVERRIDE;
+  virtual gfx::Size GetMinimumSize() const OVERRIDE;
 
  private:
   // Note: Animations can continue after then main window frame was destroyed.
@@ -255,7 +256,12 @@
   canvas->DrawPath(path, paint);
 }
 
+gfx::Size MaximizeBubbleBorder::GetMinimumSize() const {
+  return gfx::Size(kLineWidth * 2 + kArrowWidth,
+                   std::max(kLineWidth, kArrowHeight) + kLineWidth);
+}
 
+
 // BubbleMouseWatcherHost -----------------------------------------------------
 
 // The mouse watcher host which makes sure that the bubble does not get closed