Expose GetBaseline() method on RenderText.

ui/gfx/render_text.h

 // 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.
 
 #ifndef UI_GFX_RENDER_TEXT_H_
 #define UI_GFX_RENDER_TEXT_H_
 #pragma once
 
 #include <algorithm>
 #include <cstring>
@@ skipping 228 matching lines @@
   void ApplyDefaultStyle();
 
   // Returns the dominant direction of the current text.
   virtual base::i18n::TextDirection GetTextDirection() = 0;
 
   // Returns the visual movement direction corresponding to the logical end
   // of the text, considering only the dominant direction returned by
   // |GetTextDirection()|, not the direction of a particular run.
   VisualCursorDirection GetVisualDirectionOfLogicalEnd();
 
-  // Get the size in pixels of the entire string. For the height, this will
+  // Returns the size in pixels of the entire string. For the height, this will
   // return the maximum height among the different fonts in the text runs.
   // Note that this returns the raw size of the string, which does not include
   // the margin area of text shadows.
   virtual Size GetStringSize() = 0;
 
+  // Returns the common baseline of the text. The returned value is the vertical
+  // offset from the top of |display_rect| to the text baseline.

[msw, 2012/06/22 17:35:38]

nit: specify pixel units?

[Alexei Svitkine (slow), 2012/06/22 17:54:07]

Done.

+  virtual int GetBaseline() = 0;
+
   void Draw(Canvas* canvas);
 
   // Gets the SelectionModel from a visual point in local coordinates.
   virtual SelectionModel FindCursorPosition(const Point& point) = 0;
 
   // Get the visual bounds of a cursor at |selection|. These bounds typically
   // represent a vertical line, but if |insert_mode| is true they contain the
   // bounds of the associated glyph. These bounds are in local coordinates, but
   // may be outside the visible region if the text is longer than the textfield.
   // Subsequent text, cursor, or bounds changes may invalidate returned values.
@@ skipping 225 matching lines @@
 
   // Text shadows to be drawn.
   ShadowValues text_shadows_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderText);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RENDER_TEXT_H_