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

ui/gfx/render_text_harfbuzz.cc

Index: ui/gfx/render_text_harfbuzz.cc
diff --git a/ui/gfx/render_text_harfbuzz.cc b/ui/gfx/render_text_harfbuzz.cc
index 7e916ff3ae21142a633c45521e402b3b1b44ebc8..60fffc543c4b584800c240e4cc0e8878eee3fc74 100644
--- a/ui/gfx/render_text_harfbuzz.cc
+++ b/ui/gfx/render_text_harfbuzz.cc
@@ -647,6 +647,10 @@ const base::string16& RenderTextHarfBuzz::GetDisplayText() {
   return text_elided() ? display_text() : layout_text();
 }
 
+bool RenderTextHarfBuzz::MultilineSupported() const {
+  return true;
+}
+
 Size RenderTextHarfBuzz::GetStringSize() {
   const SizeF size_f = GetStringSizeF();
   return Size(std::ceil(size_f.width()), size_f.height());
@@ -1009,7 +1013,7 @@ void RenderTextHarfBuzz::DrawVisualText(Canvas* canvas) {
       renderer.SetTypeface(run.skia_face.get());
       renderer.SetTextSize(SkIntToScalar(run.font_size));
       renderer.SetFontRenderParams(run.render_params,
-                                   background_is_transparent());
+                                   subpixel_rendering_enabled());
       Range glyphs_range = run.CharRangeToGlyphRange(segment.char_range);
       scoped_ptr<SkPoint[]> positions(new SkPoint[glyphs_range.length()]);
       SkScalar offset_x =
@@ -1297,7 +1301,7 @@ bool RenderTextHarfBuzz::ShapeRunWithFont(const base::string16& text,
 
   hb_font_t* harfbuzz_font = CreateHarfBuzzFont(
       run->skia_face.get(), SkIntToScalar(run->font_size), run->render_params,
-      background_is_transparent());
+      subpixel_rendering_enabled());
 
   // TODO(vadimt): Remove ScopedTracker below once crbug.com/431326 is fixed.
   tracked_objects::ScopedTracker tracking_profile1(