Switch gfx::Range to use uint32_t instead of size_t.

ui/gfx/render_text_harfbuzz.cc

Index: ui/gfx/render_text_harfbuzz.cc
diff --git a/ui/gfx/render_text_harfbuzz.cc b/ui/gfx/render_text_harfbuzz.cc
index 39fc88cb2c14c6deb78d57a5ffe5e39c2fad7ce4..a9a05ef7d153ca44d72278555677de847ae2d403 100644
--- a/ui/gfx/render_text_harfbuzz.cc
+++ b/ui/gfx/render_text_harfbuzz.cc
@@ -460,7 +460,8 @@ class HarfBuzzLineBreaker {
     }
 
     const size_t valid_end_pos = std::max(
-        segment.char_range.start(), FindValidBoundaryBefore(text_, end_pos));
+        segment.char_range.start(),
+        static_cast<uint32_t>(FindValidBoundaryBefore(text_, end_pos)));
     if (end_pos != valid_end_pos) {
       end_pos = valid_end_pos;
       width = run.GetGlyphWidthForCharRange(
@@ -472,8 +473,9 @@ class HarfBuzzLineBreaker {
     // not separate surrogate pair or combining characters.
     // See RenderTextTest.Multiline_MinWidth for an example.
     if (width == 0 && available_width_ == max_width_) {
-      end_pos = std::min(segment.char_range.end(),
-                         FindValidBoundaryAfter(text_, end_pos + 1));
+      end_pos = std::min(
+          segment.char_range.end(),
+          static_cast<uint32_t>(FindValidBoundaryAfter(text_, end_pos + 1)));
     }
 
     return end_pos;