gfx: Make conversions from Size to SizeF be explicit.

ui/gfx/render_text.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text.h"
 
 #include <algorithm>
 #include <climits>
 
 #include "base/command_line.h"
@@ skipping 753 matching lines @@
 base::i18n::TextDirection RenderText::GetDisplayTextDirection() {
   return GetTextDirection(GetDisplayText());
 }
 
 VisualCursorDirection RenderText::GetVisualDirectionOfLogicalEnd() {
   return GetDisplayTextDirection() == base::i18n::LEFT_TO_RIGHT ?
       CURSOR_RIGHT : CURSOR_LEFT;
 }
 
 SizeF RenderText::GetStringSizeF() {
-  return GetStringSize();
+  return gfx::SizeF(GetStringSize());
 }
 
 float RenderText::GetContentWidthF() {
   const float string_size = GetStringSizeF().width();
   // The cursor is drawn one pixel beyond the int-enclosed text bounds.
   return cursor_enabled_ ? std::ceil(string_size) + 1 : string_size;
 }
 
 int RenderText::GetContentWidth() {
   return ToCeiledInt(GetContentWidthF());
@@ skipping 731 matching lines @@
 
   SetDisplayOffset(display_offset_.x() + delta_x);
 }
 
 void RenderText::DrawSelection(Canvas* canvas) {
   for (const Rect& s : GetSubstringBounds(selection()))
     canvas->FillRect(s, selection_background_focused_color_);
 }
 
 }  // namespace gfx