Cache gfx::RenderText instances in views::Label.

ui/gfx/render_text.h

Index: ui/gfx/render_text.h
diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index 415132ff0b22e5a63672a8b9ee1f70b025a2d23b..331814e38438378e1217e663cd66fc78b6e0b782 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -193,6 +193,9 @@ class GFX_EXPORT RenderText {
   static RenderText* CreateInstance();
   static RenderText* CreateInstanceForEditing();
 
+  // Returns true if the current RenderText subclass supports multilines.
+  static bool MultilineSupported();
+
   // Creates another instance of the same concrete class.
   virtual scoped_ptr<RenderText> CreateInstanceOfSameType() const = 0;
 
@@ -418,7 +421,7 @@ class GFX_EXPORT RenderText {
 
   // Sets shadows to drawn with text.
   void set_shadows(const ShadowValues& shadows) { shadows_ = shadows; }
-  const ShadowValues& shadows() { return shadows_; }
+  const ShadowValues& shadows() const { return shadows_; }
 
   typedef std::pair<Font, Range> FontSpan;
   // For testing purposes, returns which fonts were chosen for which parts of