Add float version of gfx::Range

ui/gfx/render_text_harfbuzz.h

Index: ui/gfx/render_text_harfbuzz.h
diff --git a/ui/gfx/render_text_harfbuzz.h b/ui/gfx/render_text_harfbuzz.h
index 7f3a1dcef7396fb5b5f84af79d7d12a7a63a3c15..e8d291b6b6cbe554b754172b473015ba4e68ce5b 100644
--- a/ui/gfx/render_text_harfbuzz.h
+++ b/ui/gfx/render_text_harfbuzz.h
@@ -22,11 +22,8 @@ namespace gfx {
 
 namespace internal {
 
-// TODO(ckocagil): Make Range a template class and RangeF an instance of it.
-typedef std::pair<float, float> RangeF;
-
 // Applies std::round to the start and end values of the given RangeF.
-Range GFX_EXPORT RoundRangeF(const RangeF& range_f);
+GFX_EXPORT Range RoundRangeF(const RangeF& range_f);
 
 struct GFX_EXPORT TextRunHarfBuzz {
   TextRunHarfBuzz();