Adds MSAA/IAccessible exposure of web content.

chrome/browser/browser_accessibility_manager.h

+// Copyright (c) 2006-2008 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 CHROME_BROWSER_BROWSER_ACCESSIBILITY_MANAGER_H_
+#define CHROME_BROWSER_BROWSER_ACCESSIBILITY_MANAGER_H_
+
+#include <oaidl.h>  // Needed for VARIANT structure.
+#include <hash_map>
+
+#include "base/singleton.h"
+#include "chrome/common/notification_service.h"
+#include "chrome/common/render_messages.h"
+
+class BrowserAccessibility;
+class RenderProcessHost;
+class RenderWidgetHost;
+
+// Member variable structure, used in instance hashmap.
+struct UniqueMembers {
+  RenderWidgetHost* render_widget_host_;
+  HWND parent_hwnd_;
+
+  UniqueMembers(HWND parent_hwnd, RenderWidgetHost* render_widget_host)
+    : parent_hwnd_(parent_hwnd),
+      render_widget_host_(render_widget_host) {
+  }
+};
+
+typedef stdext::hash_map<int, UniqueMembers*> InstanceMap;
+typedef stdext::hash_map<RenderProcessHost*, BrowserAccessibility*>
+    RenderProcessHostMap;
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// BrowserAccessibilityManager
+//
+// Used to manage instance creation and memory handling for browser side
+// accessibility. A singleton class. It implements NotificationObserver to
+// ensure that a termination of a renderer process gets propagated to the
+// active BrowserAccessibility instances calling into it. Each such instance
+// will upon such an event be set to an inactive state, failing calls from the
+// assistive technology gracefully.
+////////////////////////////////////////////////////////////////////////////////
+class BrowserAccessibilityManager : public NotificationObserver {
+ public:
+  // Gets the singleton BrowserAccessibilityManager object. The first time this
+  // method is called, a CacheManagerHost object is constructed and returned.
+  // Subsequent calls will return the same object.
+  static BrowserAccessibilityManager* Instance();
+
+  // Creates an instance of BrowserAccessibility, initializes it and sets the
+  // iaccessible_id and parent_id.
+  STDMETHODIMP CreateAccessibilityInstance(REFIID iid,
+                                           int iaccessible_id,
+                                           int instance_id,
+                                           void** interface_ptr);
+
+  // Composes and sends a message for requesting needed accessibility
+  // information. Unused LONG input parameters should be NULL, and the VARIANT
+  // an empty, valid instance.
+  bool RequestAccessibilityInfo(int iaccessible_id,
+                                int instance_id,
+                                int iaccessible_func_id,
+                                VARIANT var_id,
+                                LONG input1,
+                                LONG input2);
+
+  // Wrapper function, for cleaner code.
+  ViewHostMsg_Accessibility_Out_Params response();
+
+  // Retrieves the parent HWND connected to the provided id.
+  HWND parent_hwnd(int id);
+
+  // Mutator, needed since constructor does not take any arguments, and to keep
+  // instance accessor clean.
+  int SetMembers(BrowserAccessibility* browser_acc,
+                  HWND parent_hwnd,
+                  RenderWidgetHost* render_widget_host);
+
+  // NotificationObserver implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+ protected:
+  // This class is a singleton.  Do not instantiate directly.
+  BrowserAccessibilityManager();
+  friend DefaultSingletonTraits<BrowserAccessibilityManager>;
+
+  ~BrowserAccessibilityManager();
+
+ private:
+  // Caching of the unique member variables used to handle browser accessibility
+  // requests from multiple processes.
+  InstanceMap instance_map_;
+  int instance_id_;
+
+  // Reverse mapping to track which RenderProcessHosts are active. If a
+  // RenderProcessHost is found to be terminated, it should be removed from this
+  // mapping, and the connected BrowserAccessibility ids/instances invalidated.
+  RenderProcessHostMap render_process_host_map_;
+
+  ViewHostMsg_Accessibility_Out_Params out_params_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManager);
+};
+#endif  // CHROME_BROWSER_BROWSER_ACCESSIBILITY_MANAGER_H_