WIP: Modified AXPosition to work with objects with both embedded object characters and text.

ui/accessibility/ax_position.h

Index: ui/accessibility/ax_position.h
diff --git a/ui/accessibility/ax_position.h b/ui/accessibility/ax_position.h
index 8a1cf0dbffc765c3c2acebdcedaec996b7e2ea34..4c5e3ecd7cdbb1c6a039d7c9b791e6d6e3ebdb12 100644
--- a/ui/accessibility/ax_position.h
+++ b/ui/accessibility/ax_position.h
@@ -278,13 +278,14 @@ class AXPosition {
       for (int i = 0; i < copy->AnchorChildCount(); ++i) {
         AXPositionInstance child = copy->CreateChildPositionAt(i);
         DCHECK(child);
+        int child_length = child->MaxTextOffsetInParent();
         if (copy->text_offset_ >= current_offset &&
-            copy->text_offset_ < (current_offset + child->MaxTextOffset())) {
+            copy->text_offset_ < (current_offset + child_length)) {
           copy->child_index_ = i;
           break;
         }
 
-        current_offset += child->MaxTextOffset();
+        current_offset += child_length;
       }
     }
 
@@ -314,21 +315,22 @@ class AXPosition {
       for (int i = 0; i <= child_index_; ++i) {
         AXPositionInstance child = copy->CreateChildPositionAt(i);
         DCHECK(child);
+        int child_length = child->MaxTextOffsetInParent();
 
         // If the current text offset is valid, we don't touch it.
         // Otherwise, we reset it to the beginning of the current child node.
         if (i == child_index_ &&
             (copy->text_offset_ < new_offset ||
-             copy->text_offset_ > (new_offset + child->MaxTextOffset()) ||
+             copy->text_offset_ > (new_offset + child_length) ||
              // When the text offset is equal to the text's length but this is
              // not an "after text" position.
              (!copy->AtEndOfAnchor() &&
-              copy->text_offset_ == (new_offset + child->MaxTextOffset())))) {
+              copy->text_offset_ == (new_offset + child_length)))) {
           copy->text_offset_ = new_offset;
           break;
         }
 
-        new_offset += child->MaxTextOffset();
+        new_offset += child_length;
       }
     }
 
@@ -1042,8 +1044,12 @@ class AXPosition {
   virtual void AnchorParent(int* tree_id, int32_t* parent_id) const = 0;
   virtual AXNodeType* GetNodeInTree(int tree_id, int32_t node_id) const = 0;
   // Returns the length of the text that is present inside the anchor node,
-  // including any text found in descendant nodes.
+  // including any text found in descendant text nodes.
   virtual int MaxTextOffset() const = 0;
+  // Returns the length of text that this anchor node takes up in its parent.
+  // On some platforms, embedded objects are represented in their parent with a
+  // single embedded object character.
+  virtual int MaxTextOffsetInParent() const { return MaxTextOffset(); }
   virtual bool IsInLineBreak() const = 0;
   virtual std::vector<int32_t> GetWordStartOffsets() const = 0;
   virtual std::vector<int32_t> GetWordEndOffsets() const = 0;