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 4d629a00a0479cefddad8a86a0d5b453e9941288..062ac703e4d0f94b3b54ce99c63d9126a86ab147 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -256,6 +256,9 @@ class GFX_EXPORT RenderText {
   bool multiline() const { return multiline_; }
   void SetMultiline(bool multiline);
 
+  // Returns true if this instance supports multiline rendering.
+  virtual bool MultilineSupported() const = 0;
+
   // TODO(ckocagil): Add vertical alignment and line spacing support instead.
   int min_line_height() const { return min_line_height_; }
   void SetMinLineHeight(int line_height);
@@ -354,6 +357,9 @@ class GFX_EXPORT RenderText {
   // |GetDisplayTextDirection()|, not the direction of a particular run.
   VisualCursorDirection GetVisualDirectionOfLogicalEnd();
 
+  // Returns the un-elided text, but replaced when obscured.

[msw, 2015/02/25 23:54:26]

nit: consider a comment matching the format of that for GetDisplayText():
"Returns the text used for layout, which may be truncated or obscured, but it
will not be elided."

[Jun Mukai, 2015/02/26 01:40:25]

Removed this, adding this was my mistake, Because Label's |render_text_| is not
elided at all, this method is not necessary.

+  const base::string16& GetAccessibleText();

[msw, 2015/02/25 23:54:26]

Let's call this GetLayoutText().

[Jun Mukai, 2015/02/26 01:40:25]

ditto

+
   // Returns the text used to display, which may be obscured, truncated or
   // elided. The subclass may compute elided text on the fly, or use
   // precomputed the elided text.
@@ -428,7 +434,7 @@ 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