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 5a1825351bdf5c8bc97b7b754e1d3be3f7c2b7ea..11f8fb64764a5feec8051ef161c9abb149dd9641 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -52,7 +52,7 @@ class SkiaTextRenderer {
 
   void SetDrawLooper(SkDrawLooper* draw_looper);
   void SetFontRenderParams(const FontRenderParams& params,
-                           bool background_is_transparent);
+                           bool subpixel_rendering_enabled);
   void SetTypeface(SkTypeface* typeface);
   void SetTextSize(SkScalar size);
   void SetFontFamilyWithStyle(const std::string& family, int font_style);
@@ -181,7 +181,7 @@ skia::RefPtr<SkTypeface> CreateSkiaTypeface(const std::string& family,
 
 // Applies the given FontRenderParams to a Skia |paint|.
 void ApplyRenderParams(const FontRenderParams& params,
-                       bool background_is_transparent,
+                       bool subpixel_rendering_enabled,
                        SkPaint* paint);
 
 }  // namespace internal
@@ -256,6 +256,9 @@ class GFX_EXPORT RenderText {
   bool multiline() const { return multiline_; }
   void SetMultiline(bool multiline);
 
+  // Returns true if this 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);
@@ -273,9 +276,11 @@ class GFX_EXPORT RenderText {
   const Rect& display_rect() const { return display_rect_; }
   void SetDisplayRect(const Rect& r);
 
-  bool background_is_transparent() const { return background_is_transparent_; }
-  void set_background_is_transparent(bool transparent) {
-    background_is_transparent_ = transparent;
+  bool subpixel_rendering_enabled() const {
+    return subpixel_rendering_enabled_;
+  }
+  void set_subpixel_rendering_enabled(bool enabled) {
+    subpixel_rendering_enabled_ = enabled;
   }
 
   const SelectionModel& selection_model() const { return selection_model_; }
@@ -426,7 +431,7 @@ 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
@@ -733,7 +738,7 @@ class GFX_EXPORT RenderText {
   bool multiline_;
 
   // Is the background transparent (either partially or fully)?

[msw, 2015/02/17 22:16:45]

nit: update comment.

-  bool background_is_transparent_;
+  bool subpixel_rendering_enabled_;
 
   // The local display area for rendering the text.
   Rect display_rect_;