Fix accessibility with out-of-process iframes.

content/browser/accessibility/browser_accessibility.cc

Index: content/browser/accessibility/browser_accessibility.cc
diff --git a/content/browser/accessibility/browser_accessibility.cc b/content/browser/accessibility/browser_accessibility.cc
index 9d4fe101afc599be1f15caf17a87cdfc0a74103b..a5b7edc7cb8235ff1024d3e82b43805a8514c109 100644
--- a/content/browser/accessibility/browser_accessibility.cc
+++ b/content/browser/accessibility/browser_accessibility.cc
@@ -60,6 +60,14 @@ bool BrowserAccessibility::PlatformIsLeaf() const {
 }
 
 uint32 BrowserAccessibility::PlatformChildCount() const {
+  if (GetBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST)) {
+    // Check if the child frame currently exists.
+    if (manager_->delegate()->AccessibilityGetChildFrame(GetId()))
+      return 1;
+
+    return 0;
+  }
+
   return PlatformIsLeaf() ? 0 : InternalChildCount();
 }
 
@@ -80,14 +88,16 @@ bool BrowserAccessibility::IsDescendantOf(
 
 BrowserAccessibility* BrowserAccessibility::PlatformGetChild(
     uint32 child_index) const {
-  DCHECK(child_index < InternalChildCount());
-  BrowserAccessibility* result = InternalGetChild(child_index);
+  DCHECK(child_index < PlatformChildCount());
+  BrowserAccessibility* result = nullptr;
 
-  if (result->HasBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST)) {
+  if (GetBoolAttribute(ui::AX_ATTR_IS_AX_TREE_HOST)) {
     BrowserAccessibilityManager* child_manager =
-        manager_->delegate()->AccessibilityGetChildFrame(result->GetId());
+        manager_->delegate()->AccessibilityGetChildFrame(GetId());
     if (child_manager)
       result = child_manager->GetRoot();
+  } else {
+    result = InternalGetChild(child_index);
   }
 
   return result;
@@ -150,7 +160,7 @@ BrowserAccessibility* BrowserAccessibility::GetParent() const {
   if (!host_node)
     return NULL;
 
-  return host_node->GetParent();
+  return host_node;
 }
 
 int32 BrowserAccessibility::GetIndexInParent() const {