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// 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,
int 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 parent RenderFrameHostImpl and an accessibility node id, look up
// all child frames or guest frames that were previously associated with this
// frame, and populate |child_frame_hosts| with all of them that resolve
// to a valid RenderFrameHostImpl.
void GetAllChildFrames(RenderFrameHostImpl* parent_frame_host,
std::vector<RenderFrameHostImpl*>* child_frame_hosts);
// 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();
RenderFrameHostImpl* GetRFHIFromFrameTreeNodeId(
RenderFrameHostImpl* parent_frame_host,
int child_frame_tree_node_id);
// This structure stores the parent-child relationship between an
// accessibility node in a parent frame and its child frame, where the
// child frame may be an iframe or the main frame of a guest browser
// plugin. It allows the accessibility code to walk both down and up
// the "composed" accessibility tree.
struct ChildFrameMapping {
ChildFrameMapping();
// The parent frame host. Required.
RenderFrameHostImpl* parent_frame_host;
// The id of the accessibility node that's the host of the child frame,
// for example the accessibility node for the <iframe> element or the
// <embed> element.
int accessibility_node_id;
// If the child frame is an iframe, this is the iframe's FrameTreeNode id,
// otherwise 0.
int child_frame_tree_node_id;
// If the child frame is a browser plugin, this is its instance id,
// otherwise 0.
int browser_plugin_instance_id;
};
std::vector<ChildFrameMapping> mappings_;
friend struct DefaultSingletonTraits<FrameAccessibility>;
};
} // namespace content
#endif // CONTENT_BROWSER_FRAME_HOST_FRAME_ACCESSIBILITY_H_
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