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

ui/views/view_text_utils.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_VIEW_TEXT_UTILS_H_
 #define UI_VIEWS_VIEW_TEXT_UTILS_H_
 #pragma once
 
 #include "base/string16.h"
 #include "ui/views/views_export.h"
 
 namespace gfx {
-class Canvas;
+class CanvasSkia;
 class Font;
 class Rect;
 class Size;
 }
 
 namespace views {
 class Label;
 class Link;
 }
 
 // This file defines utility functions for working with text in views.
 
 namespace view_text_utils {
 
 // Draws a string onto the canvas (wrapping if needed) while also keeping
 // track of where it ends so we can position a URL after the text. The
 // parameter |bounds| represents the boundary we have to work with, |position|
 // specifies where to draw the string (relative to the top left corner of the
 // |bounds| rectangle and |font| specifies the font to use when drawing. When
 // the function returns, the parameter |rect| contains where to draw the URL
 // (to the right of where we just drew the text) and |position| is updated to
 // reflect where to draw the next string after the URL.  |label| is a dummy
 // label with the correct width and origin for the text to be written; it's
 // used so that the x position can be correctly mirrored in RTL languages.
 // |text_direction_is_rtl| is true if an RTL language is being used.
 // NOTE: The reason why we need this function is because while Skia knows how
 // to wrap text appropriately, it doesn't tell us where it drew the last
 // character, which we need to position the URLs within the text.
-VIEWS_EXPORT void DrawTextAndPositionUrl(gfx::Canvas* canvas,
+VIEWS_EXPORT void DrawTextAndPositionUrl(gfx::CanvasSkia* canvas,
                                          views::Label* label,
                                          const string16& text,
                                          views::Link* link,
                                          gfx::Rect* rect,
                                          gfx::Size* position,
                                          bool text_direction_is_rtl,
                                          const gfx::Rect& bounds,
                                          const gfx::Font& font);
 
 // A helper function for DrawTextAndPositionUrl, which simply draws the text
 // from a certain starting point |position| and wraps within bounds.
 // |word_for_word| specifies whether to draw the text word for word or whether
 // to treat the text as one blurb (similar to the way URL's are treated inside
 // RTL text. For details on the other parameters, see DrawTextAndPositionUrl.
-void DrawTextStartingFrom(gfx::Canvas* canvas,
+void DrawTextStartingFrom(gfx::CanvasSkia* canvas,
                           views::Label* label,
                           const string16& text,
                           gfx::Size* position,
                           const gfx::Rect& bounds,
                           const gfx::Font& font,
                           bool text_direction_is_rtl,
                           bool word_for_word);
 
 // A simply utility function that calculates whether a word of width
 // |word_width| fits at position |position| within the |bounds| rectangle. If
 // not, |position| is updated to wrap to the beginning of the next line.
 void WrapIfWordDoesntFit(int word_width,
                          int font_height,
                          gfx::Size* position,
                          const gfx::Rect& bounds);
 
 }  // namespace view_text_utils
 
 #endif  // UI_VIEWS_VIEW_TEXT_UTILS_H_