Always aligns text at vertically center (Textfield, Label).

ui/gfx/render_text.h

Index: ui/gfx/render_text.h
diff --git a/ui/gfx/render_text.h b/ui/gfx/render_text.h
index ce0a027b7a1607a39fc7cca89e6226609875cc2a..6d998de4472580ba3e72ff6cf0ecf4324d5f7ab8 100644
--- a/ui/gfx/render_text.h
+++ b/ui/gfx/render_text.h
@@ -167,11 +167,6 @@ class GFX_EXPORT RenderText {
   }
   void SetHorizontalAlignment(HorizontalAlignment alignment);
 
-  VerticalAlignment vertical_alignment() const {
-    return vertical_alignment_;
-  }
-  void SetVerticalAlignment(VerticalAlignment alignment);
-
   const FontList& font_list() const { return font_list_; }
   void SetFontList(const FontList& font_list);
   void SetFont(const Font& font);
@@ -338,9 +333,11 @@ class GFX_EXPORT RenderText {
   // mode). Reserves room for the cursor if |cursor_enabled_| is true.
   int GetContentWidth();
 
-  // Returns the common baseline of the text. The returned value is the vertical
-  // offset from the top of |display_rect| to the text baseline, in pixels.
-  virtual int GetBaseline() = 0;
+  // Returns the common baseline of the text. The return value is the vertical
+  // offset from the top of |display_rect_| to the text baseline, in pixels.
+  // The baseline is determined from the font list and display rect, and does
+  // not depend on the text.
+  int GetBaseline();
 
   void Draw(Canvas* canvas);
 
@@ -398,6 +395,30 @@ class GFX_EXPORT RenderText {
   const std::vector<internal::Line>& lines() const { return lines_; }
   void set_lines(std::vector<internal::Line>* lines) { lines_.swap(*lines); }
 
+  // Returns the baseline of the current text.  The return value depends on
+  // the text and its layout while the return value of GetBaseline() doesn't.
+  // GetAlignmentOffset() takes into account the difference between them.
+  //
+  // We'd like a RenderText to show the text always on the same baseline
+  // regardless of the text, so the text does not jump up or down depending
+  // on the text.  However, underlying layout engines return different baselines
+  // depending on the text.  In general, layout engines determine the minimum
+  // bounding box for the text and return the baseline from the top of the
+  // bounding box.  So the baseline changes depending on font metrics used to
+  // layout the text.
+  //
+  // For example, suppose there are FontA and FontB and the baseline of FontA
+  // is smaller than the one of FontB.  If the text is laid out only with FontA,
+  // then the baseline of FontA may be returned.  If the text includes some
+  // characters which are laid out with FontB, then the baseline of FontB may
+  // be returned.
+  //
+  // GetBaseline() returns the fixed baseline regardless of the text.
+  // GetLayoutTextBaseline() returns the baseline determined by the underlying
+  // layout engine, and it changes depending on the text.  GetAlignmentOffset()
+  // returns the difference between them.
+  virtual int GetLayoutTextBaseline() = 0;
+
   const Vector2d& GetUpdatedDisplayOffset();
 
   void set_cached_bounds_and_offset_valid(bool valid) {
@@ -542,10 +563,6 @@ class GFX_EXPORT RenderText {
   // default is to align left if the application UI is LTR and right if RTL.
   HorizontalAlignment horizontal_alignment_;
 
-  // Vertical alignment of the text with respect to |display_rect_|.  The
-  // default is to align vertically centered.
-  VerticalAlignment vertical_alignment_;
-
   // The text directionality mode, defaults to DIRECTIONALITY_FROM_TEXT.
   DirectionalityMode directionality_mode_;
 
@@ -631,6 +648,11 @@ class GFX_EXPORT RenderText {
   // Get this point with GetUpdatedDisplayOffset (or risk using a stale value).
   Vector2d display_offset_;
 
+  // The baseline of the text.  This is determined from the height of the
+  // display area and the cap height of the font list so the text is vertically
+  // centered.
+  int baseline_;
+
   // The cached bounds and offset are invalidated by changes to the cursor,
   // selection, font, and other operations that adjust the visible text bounds.
   bool cached_bounds_and_offset_valid_;