Add fade eliding for Views Labels; related cleanup.

ui/gfx/text_constants.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_TEXT_CONSTANTS_H_
 #define UI_GFX_TEXT_CONSTANTS_H_
 
 namespace gfx {
 
 // TODO(msw): Distinguish between logical character stops and glyph stops?
 // TODO(msw): Merge with base::i18n::BreakIterator::BreakType.
 enum BreakType {
-  // Stop cursor movement on neighboring characters.
-  CHARACTER_BREAK = 0,
-  // Stop cursor movement on nearest word boundaries.
-  WORD_BREAK,
-  // Stop cursor movement on line ends as shown on screen.
-  LINE_BREAK,
+  CHARACTER_BREAK = 0, // Stop cursor movement on neighboring characters.
+  WORD_BREAK,          // Stop cursor movement on nearest word boundaries.
+  LINE_BREAK,          // Stop cursor movement on line ends as shown on screen.
 };
 
 // Horizontal text alignment modes.
 enum HorizontalAlignment {
-  // Align the text's left edge with that of its display area.
-  ALIGN_LEFT = 0,
-  // Align the text's center with that of its display area.
-  ALIGN_CENTER,
-  // Align the text's right edge with that of its display area.
-  ALIGN_RIGHT,
+  ALIGN_LEFT = 0, // Align the text's left edge with that of its display area.
+  ALIGN_CENTER,   // Align the text's center with that of its display area.
+  ALIGN_RIGHT,    // Align the text's right edge with that of its display area.
 };
 
 // The directionality modes used to determine the base text direction.
 enum DirectionalityMode {
-  // Use the first strong character's direction.
-  DIRECTIONALITY_FROM_TEXT = 0,
-  // Use the UI locale's text reading direction.
-  DIRECTIONALITY_FROM_UI,
-  // Use LTR regardless of content or UI locale.
-  DIRECTIONALITY_FORCE_LTR,
-  // Use RTL regardless of content or UI locale.
-  DIRECTIONALITY_FORCE_RTL,
+  DIRECTIONALITY_FROM_TEXT = 0, // Use the first strong character's direction.
+  DIRECTIONALITY_FROM_UI,       // Use the UI locale's text reading direction.
+  DIRECTIONALITY_FORCE_LTR,     // Use LTR regardless of content or UI locale.
+  DIRECTIONALITY_FORCE_RTL,     // Use RTL regardless of content or UI locale.
 };
 
 // Text styles and adornments.
 // TODO(msw): Merge with gfx::Font::FontStyle.
 enum TextStyle {
   BOLD = 0,
   ITALIC,
   STRIKE,
   DIAGONAL_STRIKE,
   UNDERLINE,
   NUM_TEXT_STYLES,
 };
 
+// Elision behaviors of text that exceeds constrained dimensions.
+enum ElideBehavior {
+  TRUNCATE = 0, // Do not elide or fade; the text may be truncated at the end.
+  ELIDE_HEAD,   // Add an ellipsis at the start of the string.
+  ELIDE_MIDDLE, // Add an ellipsis in the middle of the string.
+  ELIDE_TAIL,   // Add an ellipsis at the end of the string.
+  ELIDE_EMAIL,  // Add ellipses to username and domain substrings.
+  FADE_TAIL,    // Fade the string's end opposite of its horizontal alignment.
+};
+
 }  // namespace gfx
 
 #endif  // UI_GFX_TEXT_CONSTANTS_H_