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// 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.
#ifndef CONTENT_RENDERER_RENDERER_ACCESSIBILITY_H_
#define CONTENT_RENDERER_RENDERER_ACCESSIBILITY_H_
#pragma once
#include <vector>
#include "base/hash_tables.h"
#include "base/memory/weak_ptr.h"
#include "content/public/renderer/render_view_observer.h"
#include "third_party/WebKit/Source/WebKit/chromium/public/WebAccessibilityNotification.h"
class RenderViewImpl;
namespace WebKit {
class WebAccessibilityObject;
class WebDocument;
class WebNode;
};
namespace webkit_glue {
struct WebAccessibility;
};
// RendererAccessibility belongs to the RenderView. It's responsible for
// sending a serialized representation of WebKit's accessibility tree from
// the renderer to the browser and sending updates whenever it changes, and
// handling requests from the browser to perform accessibility actions on
// nodes in the tree (e.g., change focus, or click on a button).
class RendererAccessibility : public content::RenderViewObserver {
public:
RendererAccessibility(RenderViewImpl* render_view);
virtual ~RendererAccessibility();
// RenderView::Observer implementation.
virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
virtual void FocusedNodeChanged(const WebKit::WebNode& node) OVERRIDE;
virtual void DidFinishLoad(WebKit::WebFrame* frame) OVERRIDE;
// Called when an accessibility notification occurs in WebKit.
virtual void PostAccessibilityNotification(
const WebKit::WebAccessibilityObject& obj,
WebKit::WebAccessibilityNotification notification);
private:
// One accessibility notification from WebKit. These are queued up and
// used to send tree updates and notification messages from the
// renderer to the browser.
struct Notification {
public:
// The id of the accessibility object.
int32 id;
// The accessibility notification type.
WebKit::WebAccessibilityNotification type;
};
// In order to keep track of what nodes the browser knows about, we keep a
// representation of the browser tree - just IDs and parent/child
// relationships.
struct BrowserTreeNode {
BrowserTreeNode() : id(0) {}
~BrowserTreeNode() {}
int32 id;
std::vector<BrowserTreeNode*> children;
};
// Send queued notifications from the renderer to the browser.
void SendPendingAccessibilityNotifications();
// Update our representation of what nodes the browser has, given a
// tree of nodes.
void UpdateBrowserTree(const webkit_glue::WebAccessibility& renderer_node);
// Clear the given node and recursively delete all of its descendants
// from the browser tree. (Does not delete |browser_node|).
void ClearBrowserTreeNode(BrowserTreeNode* browser_node);
// Handlers for messages from the browser to the renderer.
void OnDoDefaultAction(int acc_obj_id);
void OnNotificationsAck();
void OnChangeScrollPosition(int acc_obj_id, int scroll_x, int scroll_y);
void OnScrollToMakeVisible(int acc_obj_id, gfx::Rect subfocus);
void OnScrollToPoint(int acc_obj_id, gfx::Point point);
void OnEnable();
void OnSetFocus(int acc_obj_id);
void OnSetTextSelection(int acc_obj_id, int start_offset, int end_offset);
// Whether or not this notification typically needs to send
// updates to its children, too.
bool ShouldIncludeChildren(const Notification& notification);
// Returns the main top-level document for this page, or NULL if there's
// no view or frame.
WebKit::WebDocument GetMainDocument();
// So we can queue up tasks to be executed later.
base::WeakPtrFactory<RendererAccessibility> weak_factory_;
// Notifications from WebKit are collected until they are ready to be
// sent to the browser.
std::vector<Notification> pending_notifications_;
// Our representation of the browser tree.
BrowserTreeNode* browser_root_;
// A map from IDs to nodes in the browser tree.
base::hash_map<int32, BrowserTreeNode*> browser_id_map_;
// The most recently observed scroll offset of the root document element.
// TODO(dmazzoni): remove once https://bugs.webkit.org/show_bug.cgi?id=73460
// is fixed.
gfx::Size last_scroll_offset_;
// Set if we are waiting for an accessibility notification ack.
bool ack_pending_;
// True if verbose logging of accessibility events is on.
bool logging_;
DISALLOW_COPY_AND_ASSIGN(RendererAccessibility);
};
#endif // CONTENT_RENDERER_RENDERER_ACCESSIBILITY_H_
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