Hook up guest browser plugins to the accessibility tree.

content/browser/frame_host/frame_accessibility.h

+// 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.
+
+#ifndef CONTENT_BROWSER_FRAME_HOST_FRAME_ACCESSIBILITY_H_
+#define CONTENT_BROWSER_FRAME_HOST_FRAME_ACCESSIBILITY_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/singleton.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class RenderFrameHostImpl;
+
+// This singleton class maintains the mappings necessary to link child frames
+// and guest frames into a single tree for accessibility. This class is only
+// used if accessibility is enabled.
+class CONTENT_EXPORT FrameAccessibility {
+ public:
+  static FrameAccessibility* GetInstance();
+
+  // Add a mapping between an accessibility node of |parent_frame_host|
+  // and the child frame with the given frame tree node id, in the same
+  // frame tree.
+  void AddChildFrame(RenderFrameHostImpl* parent_frame_host,
+                     int accessibility_node_id,
+                     int64 child_frame_tree_node_id);
+
+  // Add a mapping between an accessibility node of |parent_frame_host|
+  // and the main frame of the guest Webcontents with the given
+  // browser plugin instance id.
+  void AddGuestWebContents(RenderFrameHostImpl* parent_frame_host,
+                           int accessibility_node_id,
+                           int browser_plugin_instance_id);
+
+  // This is called when a RenderFrameHostImpl is deleted, so invalid
+  // mappings can be removed from this data structure.
+  void OnRenderFrameHostDestroyed(RenderFrameHostImpl* render_frame_host);
+
+  // Given a parent RenderFrameHostImpl and an accessibility node id, look up
+  // a child frame or guest frame that was previously associated with this
+  // frame and node id. If a mapping exists, return the resulting frame if
+  // it's valid. If it doesn't resolve to a valid RenderFrameHostImpl,
+  // returns NULL.
+  RenderFrameHostImpl* GetChild(RenderFrameHostImpl* parent_frame_host,
+                                int accessibility_node_id);
+
+  // Given a RenderFrameHostImpl, check the mapping table to see if it's
+  // the child of a node in some other frame. If so, return true and
+  // set the parent frame and accessibility node id in the parent frame,
+  // otherwise return false.
+  bool GetParent(RenderFrameHostImpl* child_frame_host,
+                 RenderFrameHostImpl** out_parent_frame_host,
+                 int* out_accessibility_node_id);
+
+ private:
+  FrameAccessibility();
+  virtual ~FrameAccessibility();
+
+  struct ChildFrameMapping {
+    ChildFrameMapping();
+
+    RenderFrameHostImpl* parent_frame_host;
+    int accessibility_node_id;
+    int64 child_frame_tree_node_id;
+    int browser_plugin_instance_id;
+  };
+
+  std::vector<ChildFrameMapping> mappings_;
+
+  friend struct DefaultSingletonTraits<FrameAccessibility>;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_ACCESSIBILITY_H_