Enable SitePerProcessAccessibilityBrowserTest on more platforms.

content/browser/frame_host/frame_accessibility.cc

 // Copyright 2014 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/frame_host/frame_accessibility.h"
 
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/render_frame_host_delegate.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
@@ skipping 143 matching lines @@
     RenderFrameHostImpl** out_parent_frame_host,
     int* out_accessibility_node_id) {
   for (std::vector<ChildFrameMapping>::iterator iter = mappings_.begin();
        iter != mappings_.end();
        ++iter) {
     if (iter->child_frame_tree_node_id) {
       FrameTreeNode* child_node =
           FrameTree::GloballyFindByID(iter->child_frame_tree_node_id);
       if (child_node &&
           child_node->current_frame_host() == child_frame_host) {
-        // We should have gotten a *direct* child of the parent frame.

[dmazzoni, 2015/01/28 19:29:00]

This ended up being too restrictive.

There's one accessibility tree for all of the frames in the same origin. So if
you have frame A with child A' (same origin) with child frame B, from an
accessibility perspective we mark B as a child of an accessibility node from
frame A. Frame A' doesn't get its own accessibility tree.

By walking up the parent chain to assert that B is a descendant of A I think it
still satisfies security concerns.

-        if (child_node->parent() !=
-            iter->parent_frame_host->frame_tree_node()) {
+        // Assert that the child node is a descendant of the parent frame in
+        // the frame tree. It may not be a direct descendant because the
+        // parent frame's accessibility tree may span multiple frames from the
+        // same origin.
+        FrameTreeNode* parent_node = iter->parent_frame_host->frame_tree_node();
+        FrameTreeNode* child_node_ancestor = child_node->parent();
+        while (child_node_ancestor && child_node_ancestor != parent_node)
+          child_node_ancestor = child_node_ancestor->parent();
+        if (child_node_ancestor != parent_node) {
           NOTREACHED();
           return false;
         }
 
         if (out_parent_frame_host)
           *out_parent_frame_host = iter->parent_frame_host;
         if (out_accessibility_node_id)
           *out_accessibility_node_id = iter->accessibility_node_id;
         return true;
       }
@@ skipping 17 matching lines @@
 }
 
 RenderFrameHostImpl* FrameAccessibility::GetRFHIFromFrameTreeNodeId(
     RenderFrameHostImpl* parent_frame_host,
     int64 child_frame_tree_node_id) {
   FrameTreeNode* child_node =
       FrameTree::GloballyFindByID(child_frame_tree_node_id);
   if (!child_node)
     return nullptr;
 
-  // We should have gotten a *direct* child of the parent frame.
-  if (child_node->parent() != parent_frame_host->frame_tree_node()) {
+  // Assert that the child node is a descendant of the parent frame in
+  // the frame tree. It may not be a direct descendant because the
+  // parent frame's accessibility tree may span multiple frames from the
+  // same origin.
+  FrameTreeNode* parent_node = parent_frame_host->frame_tree_node();
+  FrameTreeNode* child_node_ancestor = child_node->parent();
+  while (child_node_ancestor && child_node_ancestor != parent_node)
+    child_node_ancestor = child_node_ancestor->parent();
+  if (child_node_ancestor != parent_node) {
     NOTREACHED();
     return nullptr;
   }
 
   return child_node->current_frame_host();
 }
 
 }  // namespace content