Reports the position of the caret and current selection in content editables.

content/browser/accessibility/browser_accessibility_win.cc

Index: content/browser/accessibility/browser_accessibility_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index deb97efd88b3e7e093c69b205e3d321c740a3cfe..8f49caaf1e2da511cfefd30265e0eaececbdca16 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -6,6 +6,7 @@
 
 #include <UIAutomationClient.h>
 #include <UIAutomationCoreApi.h>
+#include <algorithm>

[dmazzoni, 2015/07/16 19:50:23]

Nit: don't group this with the Microsoft includes, above - put one more blank
line before it.

 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
@@ -2004,19 +2005,11 @@ STDMETHODIMP BrowserAccessibilityWin::get_caretOffset(LONG* offset) {
   if (!offset)
     return E_INVALIDARG;
 
-  // IA2 spec says that caret offset should be -1 if the object is not focused.
-  if (manager()->GetFocus(this) != this) {
-    *offset = -1;
+  int selection_start, selection_end;
+  GetSelectionOffsets(&selection_start, &selection_end);

[dmazzoni, 2015/07/16 19:50:23]

Are you 100% sure that this change isn't going to regress any existing behavior,
like for <input> and <textarea> elements? Please check carefully.

+  *offset = selection_start;
+  if (selection_start < 0)
     return S_FALSE;
-  }
-
-  *offset = 0;
-  if (IsEditableText()) {
-    int sel_start = 0;
-    if (GetIntAttribute(ui::AX_ATTR_TEXT_SEL_START,
-                        &sel_start))
-      *offset = sel_start;
-  }
 
   return S_OK;
 }
@@ -2066,15 +2059,11 @@ STDMETHODIMP BrowserAccessibilityWin::get_nSelections(LONG* n_selections) {
     return E_INVALIDARG;
 
   *n_selections = 0;
-  if (IsEditableText()) {
-    int sel_start = 0;
-    int sel_end = 0;
-    if (GetIntAttribute(ui::AX_ATTR_TEXT_SEL_START,
-                        &sel_start) &&
-        GetIntAttribute(ui::AX_ATTR_TEXT_SEL_END, &sel_end) &&
-        sel_start != sel_end)
-      *n_selections = 1;
-  }
+  int selection_start, selection_end;
+  GetSelectionOffsets(&selection_start, &selection_end);
+  if (selection_start >= 0 && selection_end >= 0 &&
+      selection_start != selection_end)
+    *n_selections = 1;
 
   return S_OK;
 }
@@ -2094,15 +2083,11 @@ STDMETHODIMP BrowserAccessibilityWin::get_selection(LONG selection_index,
 
   *start_offset = 0;
   *end_offset = 0;
-  if (IsEditableText()) {
-    int sel_start = 0;
-    int sel_end = 0;
-    if (GetIntAttribute(
-            ui::AX_ATTR_TEXT_SEL_START, &sel_start) &&
-        GetIntAttribute(ui::AX_ATTR_TEXT_SEL_END, &sel_end)) {
-      *start_offset = sel_start;
-      *end_offset = sel_end;
-    }
+  int selection_start, selection_end;
+  GetSelectionOffsets(&selection_start, &selection_end);
+  if (selection_start >= 0 && selection_end >= 0) {
+    *start_offset = selection_start;
+    *end_offset = selection_end;
   }
 
   return S_OK;
@@ -3653,6 +3638,122 @@ void BrowserAccessibilityWin::IntAttributeToIA2(
   }
 }
 
+int32 BrowserAccessibilityWin::GetHyperlinkIndexFromChild(
+    const BrowserAccessibilityWin& child) const {
+  auto iterator = std::find(
+      hyperlinks().begin(), hyperlinks().end(), child.GetId());
+  if (iterator == hyperlinks().end())
+    return -1;
+
+  return static_cast<int32>(iterator - hyperlinks().begin());
+}
+
+int32 BrowserAccessibilityWin::GetHypertextOffsetFromHyperlinkIndex(
+    int32 hyperlink_index) const {
+  auto& offsets_map = hyperlink_offset_to_index();
+  for (auto& offset_index : offsets_map)

[dmazzoni, 2015/07/16 19:50:23]

Braces around the body of the for loop since there's more than one line inside

+    if (offset_index.second == hyperlink_index)
+      return offset_index.first;
+
+  return -1;
+}
+
+int32 BrowserAccessibilityWin::GetHypertextOffsetFromChild(
+    const BrowserAccessibilityWin& child) const {
+  int32 hyperlink_index = GetHyperlinkIndexFromChild(child);
+  if (hyperlink_index < 0)
+    return -1;
+
+  return GetHypertextOffsetFromHyperlinkIndex(hyperlink_index);
+}
+
+int32 BrowserAccessibilityWin::GetHypertextOffsetFromDescendant(
+    const BrowserAccessibilityWin& descendant) const {
+  auto parent_object = descendant.GetParent()->ToBrowserAccessibilityWin();
+  auto current_object = const_cast<BrowserAccessibilityWin*>(&descendant);
+  while (parent_object && parent_object != this) {
+    current_object = parent_object;
+    parent_object = current_object->GetParent()->ToBrowserAccessibilityWin();
+  }
+  if (!parent_object)
+    return -1;
+
+  return parent_object->GetHypertextOffsetFromChild(*current_object);
+}
+
+int BrowserAccessibilityWin::GetSelectionAnchor() const {
+  BrowserAccessibility* root = manager()->GetRoot();
+  int32 anchor_id;
+  if (!root || !root->GetIntAttribute(ui::AX_ATTR_ANCHOR_OBJECT_ID, &anchor_id))
+    return -1;
+
+  BrowserAccessibilityWin* anchor_object = manager()->GetFromID(
+      anchor_id)->ToBrowserAccessibilityWin();
+  if (!anchor_object)
+    return -1;
+
+  if (anchor_object->IsDescendantOf(this))
+    return GetHypertextOffsetFromDescendant(*anchor_object);
+
+  if (IsDescendantOf(anchor_object)) {
+    int anchor_offset;
+    if (!root->GetIntAttribute(ui::AX_ATTR_ANCHOR_OFFSET, &anchor_offset))
+      return -1;
+
+    return anchor_offset;
+  }
+
+  return -1;
+}
+
+int BrowserAccessibilityWin::GetSelectionFocus() const {
+  BrowserAccessibility* root = manager()->GetRoot();
+  int32 focus_id;
+  if (!root || !root->GetIntAttribute(ui::AX_ATTR_FOCUS_OBJECT_ID, &focus_id))
+    return -1;
+
+  BrowserAccessibilityWin* focus_object = manager()->GetFromID(
+      focus_id)->ToBrowserAccessibilityWin();
+  if (!focus_object)
+    return -1;
+
+  if (focus_object->IsDescendantOf(this))
+    return GetHypertextOffsetFromDescendant(*focus_object);
+
+  if (IsDescendantOf(focus_object)) {
+    int focus_offset;
+    if (!root->GetIntAttribute(ui::AX_ATTR_FOCUS_OFFSET, &focus_offset))
+      return -1;
+
+    return focus_offset;
+  }
+
+  return -1;
+}
+
+void BrowserAccessibilityWin::GetSelectionOffsets(
+    int* selection_start, int* selection_end) const {
+  if (!selection_start || !selection_end)
+    return;
+
+  if (GetIntAttribute(ui::AX_ATTR_TEXT_SEL_START, selection_start) &&
+      GetIntAttribute(ui::AX_ATTR_TEXT_SEL_END, selection_end)) {
+    return;
+  }
+
+  *selection_start = GetSelectionAnchor();
+  *selection_end = GetSelectionFocus();
+  if (*selection_start < 0 || *selection_end < 0)
+    return;
+
+  if (*selection_end < *selection_start)
+    std::swap(*selection_start, *selection_end);

[dmazzoni, 2015/07/16 19:50:23]

Are you sure this is correct? I think IA2 might support the selection start and
end being reversed indicating that the selection focus is at the beginning
rather than the end. Please verify and manually test with selections that go
both directions.

+
+  // IA2 Spec says that the end of the selection should be after the last
+  // embedded object character that is part of the selection.
+  ++(*selection_end);
+}
+
 base::string16 BrowserAccessibilityWin::GetNameRecursive() const {
   if (!name().empty()) {
     return name();