Add RenderText DirectionalityMode enum and support; etc.

ui/gfx/text_constants.h

Index: ui/gfx/text_constants.h
diff --git a/ui/gfx/text_constants.h b/ui/gfx/text_constants.h
new file mode 100644
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+++ b/ui/gfx/text_constants.h
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+
+// 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,
+};
+
+// 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,
+};
+
+// 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,
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_TEXT_CONSTANTS_H_