Add GetMinimumSize() for Labels and ensure it's zero for empty Links.

ui/views/controls/styled_label.h

Index: ui/views/controls/styled_label.h
===================================================================
--- ui/views/controls/styled_label.h	(revision 239550)
+++ ui/views/controls/styled_label.h	(working copy)
@@ -5,8 +5,8 @@
 #ifndef UI_VIEWS_CONTROLS_STYLED_LABEL_H_
 #define UI_VIEWS_CONTROLS_STYLED_LABEL_H_
 
+#include <list>
 #include <map>
-#include <queue>
 
 #include "base/basictypes.h"
 #include "base/strings/string16.h"
@@ -85,6 +85,9 @@
   virtual int GetHeightForWidth(int w) OVERRIDE;
   virtual void Layout() OVERRIDE;
   virtual void PreferredSizeChanged() OVERRIDE;
+  virtual void ViewHierarchyChanged(
+      const ViewHierarchyChangedDetails& details) OVERRIDE;
+  virtual void VisibilityChanged(View* starting_from, bool is_visible) OVERRIDE;
 
   // LinkListener implementation:
   virtual void LinkClicked(Link* source, int event_flags) OVERRIDE;
@@ -103,12 +106,13 @@
     gfx::Range range;
     RangeStyleInfo style_info;
   };
+  typedef std::list<StyleRange> StyleRanges;
 
   // Calculates how to layout child views, creates them and sets their size
   // and position. |width| is the horizontal space, in pixels, that the view
   // has to work with. If |dry_run| is true, the view hierarchy is not touched.
-  // The return value is the height in pixels.
-  int CalculateAndDoLayout(int width, bool dry_run);
+  // The return value is the necessary size.
+  gfx::Size CalculateAndDoLayout(int width, bool dry_run);
 
   // The text to display.
   string16 text_;
@@ -121,7 +125,7 @@
   StyledLabelListener* listener_;
 
   // The ranges that should be linkified, sorted by start position.
-  std::priority_queue<StyleRange> style_ranges_;
+  StyleRanges style_ranges_;
 
   // A mapping from a view to the range it corresponds to in |text_|. Only views
   // that correspond to ranges with is_link style set will be added to the map.
@@ -131,6 +135,10 @@
   // to avoid repeated calculation.
   gfx::Size calculated_size_;
 
+  // Saves the most recent value of IsDrawn() as of the last call to
+  // GetInsets(), since if this changes, we may need to recalulate our size.
+  mutable bool is_drawn_;
+
   // Background color on which the label is drawn, for auto color readability.
   SkColor displayed_on_background_color_;
   bool displayed_on_background_color_set_;