Fixed word and line navigation in multi-line text fields.

content/browser/accessibility/browser_accessibility.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 CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_H_
 
 #include <map>
 #include <utility>
 #include <vector>
@@ skipping 96 matching lines @@
   // top-left corner of the overall web area. Only valid when the
   // role is WebAXRoleStaticText.
   gfx::Rect GetLocalBoundsForRange(int start, int len) const;
 
   // Same as GetLocalBoundsForRange, in screen coordinates. Only valid when
   // the role is WebAXRoleStaticText.
   gfx::Rect GetGlobalBoundsForRange(int start, int len) const;
 
   // Searches in the given text and from the given offset until the start of
   // the next or previous word is found and returns its position.
+  // In case there is no word boundary before or after the given offset, it
+  // returns one past the last character, i.e. the text's length.
+  // If the given offset is already at the start of a word, returns the start
+  // of the next word if the search is forwards and the given offset if it is
+  // backwards.
+  // If the start offset is equal to -1 and the search is in the forwards
+  // direction, returns the start boundary of the first word.
+  // Start offsets that are not in the range -1 to text length are invalid.
   int GetWordStartBoundary(
       int start, ui::TextBoundaryDirection direction) const;
 
   // Returns the deepest descendant that contains the specified point
   // (in global screen coordinates).
   BrowserAccessibility* BrowserAccessibilityForPoint(const gfx::Point& point);
 
   // Marks this object for deletion, releases our reference to it, and
   // nulls out the pointer to the underlying AXNode.  May not delete
   // the object immediately due to reference counting.
@@ skipping 150 matching lines @@
   // its nearest scrollable ancestor) to local bounds (which are relative
   // to the top of the web accessibility tree).
   gfx::Rect ElementBoundsToLocalBounds(gfx::Rect bounds) const;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibility);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_H_