Implement initial support for nesting one ax tree in another.

content/browser/accessibility/browser_accessibility.cc

 // 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.
 
 #include "content/browser/accessibility/browser_accessibility.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/accessibility/browser_accessibility_manager.h"
+#include "content/browser/accessibility/frame_tree_accessibility.h"
 #include "content/common/accessibility_messages.h"
 
 namespace content {
 
 #if !defined(OS_MACOSX) && \
     !defined(OS_WIN) && \
     !defined(OS_ANDROID)
 // We have subclassess of BrowserAccessibility on Mac and Win. For any other
 // platform, instantiate the base class.
 // static
 BrowserAccessibility* BrowserAccessibility::Create() {
   return new BrowserAccessibility();
 }
 #endif
 
 BrowserAccessibility::BrowserAccessibility()
     : manager_(NULL),
-      node_(NULL) {
+      node_(NULL),
+      child_frame_id_(0) {

[David Tseng, 2014/05/01 18:07:54]

Maybe the id should be a uint32?

[dmazzoni, 2014/05/05 07:17:57]

Done.

 }
 
 BrowserAccessibility::~BrowserAccessibility() {
 }
 
 void BrowserAccessibility::Init(BrowserAccessibilityManager* manager,
     ui::AXNode* node) {
   manager_ = manager;
   node_ = node;
 }
@@ skipping 16 matching lines @@
     case ui::AX_ROLE_STATIC_TEXT:
     case ui::AX_ROLE_TEXT_AREA:
     case ui::AX_ROLE_TEXT_FIELD:
       return true;
     default:
       return false;
   }
 }
 
 uint32 BrowserAccessibility::PlatformChildCount() const {
-  return PlatformIsLeaf() ? 0 : InternalChildCount();
+  if (!child_frame_id_)

[David Tseng, 2014/05/01 18:07:54]

So, 0 means no iframe? Would it make sense to define that as a named constant?

[dmazzoni, 2014/05/05 07:17:57]

Done.

+    return PlatformIsLeaf() ? 0 : InternalChildCount();
+  FrameTreeAccessibility* frames = FrameTreeAccessibility::GetInstance();
+  BrowserAccessibilityManager* child_manager =
+      frames->FindAccessibilityManagerById(child_frame_id_);
+  return child_manager ? 1 : 0;
 }
 
 bool BrowserAccessibility::IsNative() const {
   return false;
 }
 
 bool BrowserAccessibility::IsDescendantOf(
     BrowserAccessibility* ancestor) {
   if (this == ancestor) {
     return true;
   } else if (GetParent()) {
     return GetParent()->IsDescendantOf(ancestor);
   }
 
   return false;
 }
 
 BrowserAccessibility* BrowserAccessibility::PlatformGetChild(
     uint32 child_index) const {
+  if (child_index == 0 && child_frame_id_ != 0) {

[David Tseng, 2014/05/01 18:07:54]

A named constant would help the readability of this statement.

[David Tseng, 2014/05/01 18:07:54]

Crazy question...but can an iframe element have children besides another
document? (e.g. scroll bars, groups, etc).

[dmazzoni, 2014/05/05 07:17:57]

Done.

[dmazzoni, 2014/05/05 07:17:57]

No - but even if that were the case that shouldn't really matter, in Blink we
could just add a mock node in the middle. On the browser side we really don't
need to care about what these nodes are, we just replace any children with a
link to the root node of another tree.

Anything that says iframe here should be illustrative - the implementation here
should be more general than that and should apply to any way to embed one tree
in another, like <webview>.

+    FrameTreeAccessibility* frames = FrameTreeAccessibility::GetInstance();
+    BrowserAccessibilityManager* child_manager =
+        frames->FindAccessibilityManagerById(child_frame_id_);
+    return child_manager ? child_manager->GetRoot() : NULL;
+  }
+
   DCHECK(child_index < InternalChildCount());
   return InternalGetChild(child_index);
 }
 
 BrowserAccessibility* BrowserAccessibility::GetPreviousSibling() {
   if (GetParent() && GetIndexInParent() > 0)
     return GetParent()->InternalGetChild(GetIndexInParent() - 1);
 
   return NULL;
 }
@@ skipping 19 matching lines @@
     uint32 child_index) const {
   if (!node_ || !manager_)
     return NULL;
   return manager_->GetFromAXNode(node_->children()[child_index]);
 }
 
 BrowserAccessibility* BrowserAccessibility::GetParent() const {
   if (!node_ || !manager_)
     return NULL;
   ui::AXNode* parent = node_->parent();
-  return parent ? manager_->GetFromAXNode(parent) : NULL;
+  if (parent)
+    return manager_->GetFromAXNode(parent);
+  return manager_->GetCrossFrameParent();
 }
 
 int32 BrowserAccessibility::GetIndexInParent() const {
   return node_ ? node_->index_in_parent() : -1;
 }
 
 int32 BrowserAccessibility::GetId() const {
   return node_ ? node_->id() : -1;
 }
 
@@ skipping 537 matching lines @@
 int BrowserAccessibility::GetStaticTextLenRecursive() const {
   if (GetRole() == ui::AX_ROLE_STATIC_TEXT)
     return static_cast<int>(GetStringAttribute(ui::AX_ATTR_VALUE).size());
 
   int len = 0;
   for (size_t i = 0; i < InternalChildCount(); ++i)
     len += InternalGetChild(i)->GetStaticTextLenRecursive();
   return len;
 }
 
+void BrowserAccessibility::SetChildFrameId(int child_frame_id) {
+  child_frame_id_ = child_frame_id;
+  manager_->NotifyAccessibilityEvent(ui::AX_EVENT_CHILDREN_CHANGED, this);
+}
+
 }  // namespace content