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

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 4346916bcf8968ed57e883fea9d29efec8f6f64a..50acc4de62da7804fd3aa8179dd77d4f3ba4d6de 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -25,7 +25,7 @@ struct SkPoint;
 
 namespace gfx {
 
-class Canvas;
+class CanvasSkia;
 class RenderTextTest;
 struct StyleRange;
 
@@ -34,7 +34,7 @@ namespace internal {
 // Internal helper class used by derived classes to draw text through Skia.
 class SkiaTextRenderer {
  public:
-  explicit SkiaTextRenderer(Canvas* canvas);
+  explicit SkiaTextRenderer(CanvasSkia* canvas);
   ~SkiaTextRenderer();
 
   void SetFontSmoothingSettings(bool enable_smoothing, bool enable_lcd_text);
@@ -248,7 +248,7 @@ class UI_EXPORT RenderText {
   // Get the width of the entire string.
   virtual int GetStringWidth() = 0;
 
-  void Draw(Canvas* canvas);
+  void Draw(CanvasSkia* canvas);
 
   // Gets the SelectionModel from a visual point in local coordinates.
   virtual SelectionModel FindCursorPosition(const Point& point) = 0;
@@ -336,7 +336,7 @@ class UI_EXPORT RenderText {
   virtual void EnsureLayout() = 0;
 
   // Draw the text.
-  virtual void DrawVisualText(Canvas* canvas) = 0;
+  virtual void DrawVisualText(CanvasSkia* canvas) = 0;
 
   // Like text() except that it returns asterisks or bullets if this is an
   // obscured field.
@@ -391,8 +391,8 @@ class UI_EXPORT RenderText {
   void UpdateCachedBoundsAndOffset();
 
   // Draw the selection and cursor.
-  void DrawSelection(Canvas* canvas);
-  void DrawCursor(Canvas* canvas);
+  void DrawSelection(CanvasSkia* canvas);
+  void DrawCursor(CanvasSkia* canvas);
 
   // Logical UTF-16 string data to be drawn.
   string16 text_;