Make BrowserAccessibilityManager cross platform. Step 2.

chrome/browser/accessibility/browser_accessibility_manager.h

 // Copyright (c) 2010 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_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_
 #define CHROME_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_
 #pragma once
 
-#include "build/build_config.h"
-
-#if defined(OS_WIN)
-#include <oleacc.h>
-#endif
-
 #include <vector>
 
+#include "base/hash_tables.h"
+#include "base/scoped_ptr.h"
+#include "build/build_config.h"
+#include "chrome/common/render_messages_params.h"
 #include "gfx/native_widget_types.h"
 #include "webkit/glue/webaccessibility.h"
 
-struct ViewHostMsg_AccessibilityNotification_Params;
+
+class BrowserAccessibility;
+#if defined(OS_WIN)
+class BrowserAccessibilityManagerWin;
+#endif
 
 using webkit_glue::WebAccessibility;
 
 // Class that can perform actions on behalf of the BrowserAccessibilityManager.
 class BrowserAccessibilityDelegate {
  public:
   virtual ~BrowserAccessibilityDelegate() {}
   virtual void SetAccessibilityFocus(int acc_obj_id) = 0;
   virtual void AccessibilityDoDefaultAction(int acc_obj_id) = 0;
   virtual bool HasFocus() = 0;
 };
 
+class BrowserAccessibilityFactory {
+ public:
+  virtual ~BrowserAccessibilityFactory() {}
+
+  // Create an instance of BrowserAccessibility and return a new
+  // reference to it.
+  virtual BrowserAccessibility* Create();
+};
+
 // Manages a tree of BrowserAccessibility objects.
 class BrowserAccessibilityManager {
  public:
   // Creates the platform specific BrowserAccessibilityManager. Ownership passes
   // to the caller.
   static BrowserAccessibilityManager* Create(
-    gfx::NativeWindow parent_window,
-    const webkit_glue::WebAccessibility& src,
-    BrowserAccessibilityDelegate* delegate);
+    gfx::NativeView parent_view,
+    const WebAccessibility& src,
+    BrowserAccessibilityDelegate* delegate,
+    BrowserAccessibilityFactory* factory = new BrowserAccessibilityFactory());
 
   virtual ~BrowserAccessibilityManager();
 
+  virtual void NotifyAccessibilityEvent(
+      ViewHostMsg_AccessibilityNotification_Params::NotificationType n,
+      BrowserAccessibility* node) = 0;
+
+  // Returns the next unique child id.
+  static int32 GetNextChildID();
+
+  // Return a pointer to the root of the tree, does not make a new reference.
+  BrowserAccessibility* GetRoot();
+
+  // Removes the BrowserAccessibility child_id from the manager.
+  void Remove(int32 child_id);
+
+  // Return a pointer to the object corresponding to the given child_id,
+  // does not make a new reference.
+  BrowserAccessibility* GetFromChildID(int32 child_id);
+
   // Called to notify the accessibility manager that its associated native
-  // window got focused.
-  virtual void GotFocus() = 0;
+  // view got focused.
+  void GotFocus();
+
+  // Tell the renderer to set focus to this node.
+  void SetFocus(const BrowserAccessibility& node);
+
+  // Tell the renderer to do the default action for this node.
+  void DoDefaultAction(const BrowserAccessibility& node);
 
   // Called when the renderer process has notified us of about tree changes.
   // Send a notification to MSAA clients of the change.
   void OnAccessibilityNotifications(
     const std::vector<ViewHostMsg_AccessibilityNotification_Params>& params);
 
-  gfx::NativeWindow GetParentWindow();
+  gfx::NativeView GetParentView();
 
 #if defined(OS_WIN)
-  virtual IAccessible* GetRootAccessible() = 0;
+  BrowserAccessibilityManagerWin* toBrowserAccessibilityManagerWin();
 #endif
 
+  // Return the object that has focus, if it's a descandant of the
+  // given root (inclusive). Does not make a new reference.
+  BrowserAccessibility* GetFocus(BrowserAccessibility* root);
+
  protected:
-  explicit BrowserAccessibilityManager(gfx::NativeWindow parent_window);
-
-  virtual void OnAccessibilityObjectStateChange(
-      const webkit_glue::WebAccessibility& acc_obj) = 0;
-  virtual void OnAccessibilityObjectChildrenChange(
-      const webkit_glue::WebAccessibility& acc_obj) = 0;
-  virtual void OnAccessibilityObjectFocusChange(
-      const webkit_glue::WebAccessibility& acc_obj) = 0;
-  virtual void OnAccessibilityObjectLoadComplete(
-      const webkit_glue::WebAccessibility& acc_obj) = 0;
-  virtual void OnAccessibilityObjectValueChange(
-      const webkit_glue::WebAccessibility& acc_obj) = 0;
-  virtual void OnAccessibilityObjectTextChange(
-      const webkit_glue::WebAccessibility& acc_obj) = 0;
+  BrowserAccessibilityManager(
+      gfx::NativeView parent_view,
+      const WebAccessibility& src,
+      BrowserAccessibilityDelegate* delegate,
+      BrowserAccessibilityFactory* factory);
 
  private:
-  // The parent window.
-  gfx::NativeWindow parent_window_;
+  void OnAccessibilityObjectStateChange(
+      const WebAccessibility& acc_obj);
+  void OnAccessibilityObjectChildrenChange(
+      const WebAccessibility& acc_obj);
+  void OnAccessibilityObjectFocusChange(
+      const WebAccessibility& acc_obj);
+  void OnAccessibilityObjectLoadComplete(
+      const WebAccessibility& acc_obj);
+  void OnAccessibilityObjectValueChange(
+      const WebAccessibility& acc_obj);
+  void OnAccessibilityObjectTextChange(
+      const WebAccessibility& acc_obj);
+
+  // Recursively compare the IDs of our subtree to a new subtree received
+  // from the renderer and return true if their IDs match exactly.
+  bool CanModifyTreeInPlace(
+      BrowserAccessibility* current_root,
+      const WebAccessibility& new_root);
+
+  // Recursively modify a subtree (by reinitializing) to match a new
+  // subtree received from the renderer process. Should only be called
+  // if CanModifyTreeInPlace returned true.
+  void ModifyTreeInPlace(
+      BrowserAccessibility* current_root,
+      const WebAccessibility& new_root);
+
+  // Update the accessibility tree with an updated WebAccessibility tree or
+  // subtree received from the renderer process. First attempts to modify
+  // the tree in place, and if that fails, replaces the entire subtree.
+  // Returns the updated node or NULL if no node was updated.
+  BrowserAccessibility* UpdateTree(
+      const WebAccessibility& acc_obj);
+
+  // Recursively build a tree of BrowserAccessibility objects from
+  // the WebAccessibility tree received from the renderer process.
+  BrowserAccessibility* CreateAccessibilityTree(
+      BrowserAccessibility* parent,
+      int child_id,
+      const WebAccessibility& src,
+      int index_in_parent);
+
+ protected:
+  // The next unique id for a BrowserAccessibility instance.
+  static int32 next_child_id_;
+
+  // The parent view.
+  gfx::NativeView parent_view_;
+
+  // The object that can perform actions on our behalf.
+  BrowserAccessibilityDelegate* delegate_;
+
+  // Factory to create BrowserAccessibility objects (for dependency injection).
+  scoped_ptr<BrowserAccessibilityFactory> factory_;
+
+  // The root of the tree of IAccessible objects and the element that
+  // currently has focus, if any.
+  BrowserAccessibility* root_;
+  BrowserAccessibility* focus_;
+
+  // A mapping from the IDs of objects in the renderer, to the child IDs
+  // we use internally here.
+  base::hash_map<int, int32> renderer_id_to_child_id_map_;
+
+  // A mapping from child IDs to BrowserAccessibility objects.
+  base::hash_map<int32, BrowserAccessibility*> child_id_map_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManager);
 };
 
 #endif  // CHROME_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_