Implement more IAccessibleText in NativeViewAccessibilityWin.

This enables NVDA to provide more accessibility for the omnibox.
This code was previously implemented in BrowserAccessibilityWin,
so as much of the logic as possible is abstracted into
a new utility function in ui/base/accessibility.

BUG=102485
TEST=Explore omnibox with NVDA

Review URL: http://codereview.chromium.org/8437063

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@108718 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 48 insertions, 89 deletions

diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index 7be2664..5d23cdc 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -11,6 +11,7 @@
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
 #include "content/common/view_messages.h"
 #include "net/base/escape.h"
+#include "ui/base/accessibility/accessible_text_utils.h"
 
 using webkit_glue::WebAccessibility;
 
@@ -1746,8 +1747,10 @@ STDMETHODIMP BrowserAccessibilityWin::get_textAtOffset(
 
   const string16& text_str = TextForIAccessibleText();
 
-  *start_offset = FindBoundary(text_str, boundary_type, offset, -1);
-  *end_offset = FindBoundary(text_str, boundary_type, offset, 1);
+  *start_offset = FindBoundary(
+      text_str, boundary_type, offset, ui::BACKWARDS_DIRECTION);
+  *end_offset = FindBoundary(
+      text_str, boundary_type, offset, ui::FORWARDS_DIRECTION);
   return get_text(*start_offset, *end_offset, text);
 }
 
@@ -1773,7 +1776,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_textBeforeOffset(
 
   const string16& text_str = TextForIAccessibleText();
 
-  *start_offset = FindBoundary(text_str, boundary_type, offset, -1);
+  *start_offset = FindBoundary(
+      text_str, boundary_type, offset, ui::BACKWARDS_DIRECTION);
   *end_offset = offset;
   return get_text(*start_offset, *end_offset, text);
 }
@@ -1801,7 +1805,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_textAfterOffset(
   const string16& text_str = TextForIAccessibleText();
 
   *start_offset = offset;
-  *end_offset = FindBoundary(text_str, boundary_type, offset, 1);
+  *end_offset = FindBoundary(
+      text_str, boundary_type, offset, ui::FORWARDS_DIRECTION);
   return get_text(*start_offset, *end_offset, text);
 }
 
@@ -2530,87 +2535,30 @@ void BrowserAccessibilityWin::HandleSpecialTextOffset(
   }
 }
 
+ui::TextBoundaryType BrowserAccessibilityWin::IA2TextBoundaryToTextBoundary(
+    IA2TextBoundaryType ia2_boundary) {
+  switch(ia2_boundary) {
+    case IA2_TEXT_BOUNDARY_CHAR: return ui::CHAR_BOUNDARY;
+    case IA2_TEXT_BOUNDARY_WORD: return ui::WORD_BOUNDARY;
+    case IA2_TEXT_BOUNDARY_LINE: return ui::LINE_BOUNDARY;
+    case IA2_TEXT_BOUNDARY_SENTENCE: return ui::SENTENCE_BOUNDARY;
+    case IA2_TEXT_BOUNDARY_PARAGRAPH: return ui::PARAGRAPH_BOUNDARY;
+    case IA2_TEXT_BOUNDARY_ALL: return ui::ALL_BOUNDARY;
+    default:
+      NOTREACHED();
+      return ui::CHAR_BOUNDARY;
+  }
+}
+
 LONG BrowserAccessibilityWin::FindBoundary(
     const string16& text,
-    IA2TextBoundaryType boundary,
+    IA2TextBoundaryType ia2_boundary,
     LONG start_offset,
-    LONG direction) {
-  LONG text_size = static_cast<LONG>(text.size());
-  DCHECK((start_offset >= 0 && start_offset <= text_size) ||
-         start_offset == IA2_TEXT_OFFSET_LENGTH ||
-         start_offset == IA2_TEXT_OFFSET_CARET);
-  DCHECK(direction == 1 || direction == -1);
-
+    ui::TextBoundaryDirection direction) {
   HandleSpecialTextOffset(text, &start_offset);
-
-  if (boundary == IA2_TEXT_BOUNDARY_CHAR) {
-    if (direction == 1 && start_offset < text_size)
-      return start_offset + 1;
-    else
-      return start_offset;
-  } else if (boundary == IA2_TEXT_BOUNDARY_LINE) {
-    if (direction == 1) {
-      for (int j = 0; j < static_cast<int>(line_breaks_.size()); ++j) {
-        if (line_breaks_[j] > start_offset)
-          return line_breaks_[j];
-      }
-      return text_size;
-    } else {
-      for (int j = static_cast<int>(line_breaks_.size()) - 1; j >= 0; j--) {
-        if (line_breaks_[j] <= start_offset)
-          return line_breaks_[j];
-      }
-      return 0;
-    }
-  }
-
-  LONG result = start_offset;
-  for (;;) {
-    LONG pos;
-    if (direction == 1) {
-      if (result >= text_size)
-        return text_size;
-      pos = result;
-    } else {
-      if (result <= 0)
-        return 0;
-      pos = result - 1;
-    }
-
-    switch (boundary) {
-      case IA2_TEXT_BOUNDARY_CHAR:
-      case IA2_TEXT_BOUNDARY_LINE:
-        NOTREACHED();  // These are handled above.
-        break;
-      case IA2_TEXT_BOUNDARY_WORD:
-        if (IsWhitespace(text[pos]))
-          return result;
-        break;
-      case IA2_TEXT_BOUNDARY_PARAGRAPH:
-        if (text[pos] == '\n')
-          return result;
-      case IA2_TEXT_BOUNDARY_SENTENCE:
-        // Note that we don't actually have to implement sentence support;
-        // currently IAccessibleText functions return S_FALSE so that
-        // screenreaders will handle it on their own.
-        if ((text[pos] == '.' || text[pos] == '!' || text[pos] == '?') &&
-            (pos == text_size - 1 || IsWhitespace(text[pos + 1]))) {
-          return result;
-        }
-      case IA2_TEXT_BOUNDARY_ALL:
-      default:
-        break;
-    }
-
-    if (direction > 0) {
-      result++;
-    } else if (direction < 0) {
-      result--;
-    } else {
-      NOTREACHED();
-      return result;
-    }
-  }
+  ui::TextBoundaryType boundary = IA2TextBoundaryToTextBoundary(ia2_boundary);
+  return ui::FindAccessibleTextBoundary(
+      text, line_breaks_, boundary, start_offset, direction);
 }
 
 BrowserAccessibilityWin* BrowserAccessibilityWin::GetFromRendererID(
diff --git a/content/browser/accessibility/browser_accessibility_win.h b/content/browser/accessibility/browser_accessibility_win.h
index d20b650..0af601d 100644
--- a/content/browser/accessibility/browser_accessibility_win.h
+++ b/content/browser/accessibility/browser_accessibility_win.h
@@ -23,6 +23,11 @@
 class BrowserAccessibilityManagerWin;
 class BrowserAccessibilityRelation;
 
+namespace ui {
+enum TextBoundaryDirection;
+enum TextBoundaryType;
+}
+
 using webkit_glue::WebAccessibility;
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -416,17 +421,20 @@ BrowserAccessibilityWin
   CONTENT_EXPORT STDMETHODIMP get_text(LONG start_offset, LONG end_offset,
                                        BSTR* text);
 
-  CONTENT_EXPORT STDMETHODIMP get_textAtOffset(LONG offset,
+  CONTENT_EXPORT STDMETHODIMP get_textAtOffset(
+      LONG offset,
       enum IA2TextBoundaryType boundary_type,
       LONG* start_offset, LONG* end_offset,
       BSTR* text);
 
-  CONTENT_EXPORT STDMETHODIMP get_textBeforeOffset(LONG offset,
+  CONTENT_EXPORT STDMETHODIMP get_textBeforeOffset(
+      LONG offset,
       enum IA2TextBoundaryType boundary_type,
       LONG* start_offset, LONG* end_offset,
       BSTR* text);
 
-  CONTENT_EXPORT STDMETHODIMP get_textAfterOffset(LONG offset,
+  CONTENT_EXPORT STDMETHODIMP get_textAfterOffset(
+      LONG offset,
       enum IA2TextBoundaryType boundary_type,
       LONG* start_offset, LONG* end_offset,
       BSTR* text);
@@ -677,13 +685,16 @@ BrowserAccessibilityWin
   // value of offset and returns, otherwise offset remains unchanged.
   void HandleSpecialTextOffset(const string16& text, LONG* offset);
 
-  // Search forwards (direction == 1) or backwards (direction == -1) from
-  // the given offset until the given IAccessible2 boundary (like word,
-  // sentence) is found, and return its offset.
+  // Convert from a IA2TextBoundaryType to a ui::TextBoundaryType.
+  ui::TextBoundaryType IA2TextBoundaryToTextBoundary(IA2TextBoundaryType type);
+
+  // Search forwards (direction == 1) or backwards (direction == -1)
+  // from the given offset until the given boundary is found, and
+  // return the offset of that boundary.
   LONG FindBoundary(const string16& text,
-                    IA2TextBoundaryType boundary,
+                    IA2TextBoundaryType ia2_boundary,
                     LONG start_offset,
-                    LONG direction);
+                    ui::TextBoundaryDirection direction);
 
   // Return a pointer to the object corresponding to the given renderer_id,
   // does not make a new reference.