ui/gfx: Make gfx::Canvas inherit from gfx::CanvasSkia.

ui/views/examples/text_example.cc

Index: ui/views/examples/text_example.cc
diff --git a/ui/views/examples/text_example.cc b/ui/views/examples/text_example.cc
index ae91cdaf5b77d80c9aea344b62917fa740768c47..5e0f4c73563b3e0a3e673ad8d1cf5b3ee56af23a 100644
--- a/ui/views/examples/text_example.cc
+++ b/ui/views/examples/text_example.cc
@@ -106,14 +106,14 @@ class TextExample::TextExampleView : public View {
       gfx::Rect rect(0, 0, width(), height());
       size_t characters_to_truncate_from_head =
           gfx::CanvasSkia::TruncateFadeHeadAndTail ? 10 : 0;
-      canvas->AsCanvasSkia()->DrawFadeTruncatingString(text_, fade_mode_,
+      canvas->DrawFadeTruncatingString(text_, fade_mode_,
           characters_to_truncate_from_head, font_, SK_ColorDKGRAY, rect);
       return;
     }
 #endif
 
     if (halo_) {
-      canvas->AsCanvasSkia()->DrawStringWithHalo(text_, font_, SK_ColorDKGRAY,
+      canvas->DrawStringWithHalo(text_, font_, SK_ColorDKGRAY,
           SK_ColorWHITE, 0, 0, width(), height(), text_flags_);
     } else {
       canvas->DrawStringInt(text_, font_, SK_ColorDKGRAY, 0, 0, width(),