Allow various font weights in gfx.

ui/gfx/font.h

Index: ui/gfx/font.h
diff --git a/ui/gfx/font.h b/ui/gfx/font.h
index b7a7f9da4bde09a46d90a5d22ff72562e5bfe7f9..cb0984e87a8ed8593045dc155f09e4318af95735 100644
--- a/ui/gfx/font.h
+++ b/ui/gfx/font.h
@@ -34,9 +34,21 @@ class GFX_EXPORT Font {
   // The following constants indicate the font style.
   enum FontStyle {

[Peter Kasting, 2016/03/26 00:56:51]

Didn't read previous conversations, so maybe you discussed this; should this
become "enum class Style" for parallel structure?  That would make some callers
read more clearly, since instead of:

gfx::Font::NORMAL, gfx::Font::Weight::BOLD

...as a parameter list, you get:

gfx::Font::Style::NORMAL, gfx::Font::Weight::BOLD

It may be that this would touch enough places that you'd want to do it
separately, but I raise it now in case you're already touching enough of those
places anyway to make this make sense.

[Mikus, 2016/03/29 10:55:38]

Yes, this was raised previously, we've decided to make this an enum class in a
follow-up patchset.

     NORMAL = 0,
-    BOLD = 1,
-    ITALIC = 2,
-    UNDERLINE = 4,
+    ITALIC = 1,
+    UNDERLINE = 2,
+  };
+
+  enum class Weight {
+    INVALID = -1,
+    THIN = 100,
+    EXTRA_LIGHT = 200,
+    LIGHT = 300,
+    NORMAL = 400,
+    MEDIUM = 500,
+    SEMIBOLD = 600,
+    BOLD = 700,
+    EXTRA_BOLD = 800,
+    BLACK = 900,
   };
 
   // Creates a font with the default name and style.
@@ -64,8 +76,8 @@ class GFX_EXPORT Font {
   // |size_delta| is the size in pixels to add to the current font. For example,
   // a value of 5 results in a font 5 pixels bigger than this font.
   // The style parameter specifies the new style for the font, and is a
-  // bitmask of the values: BOLD, ITALIC and UNDERLINE.
-  Font Derive(int size_delta, int style) const;
+  // bitmask of the values: ITALIC and UNDERLINE.
+  Font Derive(int size_delta, int style, gfx::Font::Weight weight) const;
 
   // Returns the number of vertical pixels needed to display characters from
   // the specified font.  This may include some leading, i.e. height may be
@@ -74,6 +86,9 @@ class GFX_EXPORT Font {
   // need to be revisited in the future.
   int GetHeight() const;
 
+  // Returns the font weight.
+  gfx::Font::Weight GetWeight() const;
+
   // Returns the baseline, or ascent, of the font.
   int GetBaseline() const;
 
@@ -118,6 +133,11 @@ class GFX_EXPORT Font {
   scoped_refptr<PlatformFont> platform_font_;
 };
 
+#ifndef NDEBUG
+GFX_EXPORT std::ostream& operator<<(std::ostream& stream,
+                                    const gfx::Font::Weight weight);
+#endif
+
 }  // namespace gfx
 
 #endif  // UI_GFX_FONT_H_