Rewrite renderer accessibility to not use WebAccessibilityCache.

content/renderer/renderer_accessibility.h

+// Copyright (c) 2011 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/task.h"
+#include "content/renderer/render_view_observer.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebAccessibilityNotification.h"
+
+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 RenderViewObserver {
+ public:
+  RendererAccessibility(RenderView* render_view);
+  virtual ~RendererAccessibility();
+
+  // RenderView::Observer implementation.
+  virtual bool OnMessageReceived(const IPC::Message& message);
+  virtual void FocusedNodeChanged(const WebKit::WebNode& node);
+  virtual void DidFinishLoad(WebKit::WebFrame* frame);
+
+  // 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() {}
+    ~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 OnAccessibilityDoDefaultAction(int acc_obj_id);
+  void OnAccessibilityNotificationsAck();
+  void OnEnableAccessibility();
+  void OnSetAccessibilityFocus(int acc_obj_id);
+
+  // 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.
+  ScopedRunnableMethodFactory<RendererAccessibility> method_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_;
+
+  // Set if we are waiting for an accessibility notification ack.
+  bool ack_pending_;
+
+  // True if verbose logging of accessibility events is on.
+  bool logging_;
+
+  // True if we've sent a load complete notification for this page already.
+  bool sent_load_complete_;
+
+  DISALLOW_COPY_AND_ASSIGN(RendererAccessibility);
+};
+
+#endif  // CONTENT_RENDERER_RENDERER_ACCESSIBILITY_H_