Allow various font weights in gfx.

ui/gfx/platform_font.h

 // 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_GFX_PLATFORM_FONT_H_
 #define UI_GFX_PLATFORM_FONT_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
+#include "ui/gfx/font.h"
 #include "ui/gfx/gfx_export.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 
 class Font;
 struct FontRenderParams;
 
 class GFX_EXPORT PlatformFont : public base::RefCounted<PlatformFont> {
  public:
   // Creates an appropriate PlatformFont implementation.
   static PlatformFont* CreateDefault();
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
   static PlatformFont* CreateFromNativeFont(NativeFont native_font);
 #endif
   // Creates a PlatformFont implementation with the specified |font_name|
   // (encoded in UTF-8) and |font_size| in pixels.
   static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
                                              int font_size);
 
   // Returns a new Font derived from the existing font.
   // |size_delta| is the size in pixels to add to the current font.
   // The style parameter specifies the new style for the font, and is a
-  // bitmask of the values: BOLD, ITALIC and UNDERLINE.
-  virtual Font DeriveFont(int size_delta, int style) const = 0;
+  // bitmask of the values: ITALIC and UNDERLINE.
+  // The weight parameter specifies the desired weight of the font.
+  virtual Font DeriveFont(int size_delta,
+                          int style,
+                          Font::Weight weight) const = 0;
 
   // Returns the number of vertical pixels needed to display characters from
   // the specified font.  This may include some leading, i.e. height may be
   // greater than just ascent + descent.  Specifically, the Windows and Mac
   // implementations include leading and the Linux one does not.  This may
   // need to be revisited in the future.
   virtual int GetHeight() = 0;
 
+  // Returns the font weight.
+  virtual Font::Weight GetWeight() const = 0;
+
   // Returns the baseline, or ascent, of the font.
   virtual int GetBaseline() = 0;
 
   // Returns the cap height of the font.
   virtual int GetCapHeight() = 0;
 
   // Returns the expected number of horizontal pixels needed to display the
   // specified length of characters. Call GetStringWidth() to retrieve the
   // actual number.
   virtual int GetExpectedTextWidth(int length) = 0;
@@ skipping 21 matching lines @@
  protected:
   virtual ~PlatformFont() {}
 
  private:
   friend class base::RefCounted<PlatformFont>;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_PLATFORM_FONT_H_