Add float version of gfx::Range

ui/gfx/render_text_unittest.cc

Index: ui/gfx/render_text_unittest.cc
diff --git a/ui/gfx/render_text_unittest.cc b/ui/gfx/render_text_unittest.cc
index 44aaa1a43b5772eefff567e04d4a8f802b97a011..30a515f4775f1af05aa0d1a4894273f00d47bdd0 100644
--- a/ui/gfx/render_text_unittest.cc
+++ b/ui/gfx/render_text_unittest.cc
@@ -18,6 +18,8 @@
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/font.h"
+#include "ui/gfx/range/range.h"
+#include "ui/gfx/range/range_f.h"
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #if defined(OS_WIN)
@@ -2104,7 +2106,7 @@ TEST_F(RenderTextTest, HarfBuzz_SubglyphGraphemeCases) {
     auto first_grapheme_bounds = run->GetGraphemeBounds(iter, 0);
     EXPECT_EQ(first_grapheme_bounds, run->GetGraphemeBounds(iter, 1));
     auto second_grapheme_bounds = run->GetGraphemeBounds(iter, 2);
-    EXPECT_EQ(first_grapheme_bounds.second, second_grapheme_bounds.first);
+    EXPECT_EQ(first_grapheme_bounds.end(), second_grapheme_bounds.start());
   }
 }