Clean-up: Renames gfx::Font's methods and removes its obsolete methods.

Applies the same renaming as http://crrev.com/142523003 and also removes obsolete methods.

Renamed methods:
- DeriveFont(size_delta, style) => Derive(size_delta, style)

Removed methods:
- DeriveFont(size_delta)
- GetAverageCharacterWidth()
  # Use GetExpectedTextWidth(1) instead.
- GetStringWidth(text)
  # Use gfx::GetStringWidth(text, font_list) instead.

BUG=265485
TEST=Run ui_unittests, views_unittests.

Review URL: https://codereview.chromium.org/138013004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251028 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ui/gfx/font_list_impl.cc b/ui/gfx/font_list_impl.cc
index b6e88948..b08d395 100644
--- a/ui/gfx/font_list_impl.cc
+++ b/ui/gfx/font_list_impl.cc
@@ -125,7 +125,7 @@
   if (!fonts_.empty()) {
     std::vector<Font> fonts = fonts_;
     for (size_t i = 0; i < fonts.size(); ++i)
-      fonts[i] = fonts[i].DeriveFont(size_delta, font_style);
+      fonts[i] = fonts[i].Derive(size_delta, font_style);
     return new FontListImpl(fonts);
   }
 
@@ -209,7 +209,7 @@
       if (font_style_ == Font::NORMAL)
         fonts_.push_back(font);
       else
-        fonts_.push_back(font.DeriveFont(0, font_style_));
+        fonts_.push_back(font.Derive(0, font_style_));
     }
   }
   return fonts_;