1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_ACCESSIBILITY_API_H_ 6 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_ACCESSIBILITY_API_H_ 7 #pragma once 8 9 #include <string> 10 #include <vector> 11 12 #include "base/callback.h" 13 #include "base/memory/singleton.h" 14 #include "base/values.h" 15 #include "chrome/browser/accessibility_events.h" 16 #include "chrome/browser/extensions/extension_function.h" 17 #include "content/common/notification_observer.h" 18 #include "content/common/notification_registrar.h" 19 20 // Observes the profile and routes accessibility notifications as events 21 // to the extension system. 22 class ExtensionAccessibilityEventRouter : public NotificationObserver { 23 public: 24 // Single instance of the event router. 25 static ExtensionAccessibilityEventRouter* GetInstance(); 26 27 // Safe to call multiple times. 28 void ObserveProfile(Profile* profile); 29 30 // Get the dict representing the last control that received an 31 // OnControlFocus event. last_focused_control_dict()32 DictionaryValue* last_focused_control_dict() { 33 return &last_focused_control_dict_; 34 } 35 36 // Accessibility support is disabled until an extension expicitly enables 37 // it, so that this extension api has no impact on Chrome's performance 38 // otherwise. These methods handle enabling, disabling, querying the 39 // status, and installing callbacks to execute when accessibility support 40 // is enabled or disabled. 41 void SetAccessibilityEnabled(bool enabled); 42 bool IsAccessibilityEnabled() const; 43 typedef Callback0::Type Callback; 44 void AddOnEnabledListener(Callback* callback); 45 void AddOnDisabledListener(Callback* callback); 46 47 private: 48 friend struct DefaultSingletonTraits<ExtensionAccessibilityEventRouter>; 49 50 ExtensionAccessibilityEventRouter(); 51 virtual ~ExtensionAccessibilityEventRouter(); 52 53 // NotificationObserver::Observe. 54 virtual void Observe(NotificationType type, 55 const NotificationSource& source, 56 const NotificationDetails& details); 57 58 void OnWindowOpened(const AccessibilityWindowInfo* details); 59 void OnWindowClosed(const AccessibilityWindowInfo* details); 60 void OnControlFocused(const AccessibilityControlInfo* details); 61 void OnControlAction(const AccessibilityControlInfo* details); 62 void OnTextChanged(const AccessibilityControlInfo* details); 63 void OnMenuOpened(const AccessibilityMenuInfo* details); 64 void OnMenuClosed(const AccessibilityMenuInfo* details); 65 66 void DispatchEvent(Profile* profile, 67 const char* event_name, 68 const std::string& json_args); 69 70 // Used for tracking registrations to history service notifications. 71 NotificationRegistrar registrar_; 72 73 DictionaryValue last_focused_control_dict_; 74 75 bool enabled_; 76 std::vector<Callback*> on_enabled_listeners_; 77 std::vector<Callback*> on_disabled_listeners_; 78 79 DISALLOW_COPY_AND_ASSIGN(ExtensionAccessibilityEventRouter); 80 }; 81 82 // API function that enables or disables accessibility support. Event 83 // listeners are only installed when accessibility support is enabled, to 84 // minimize the impact. 85 class SetAccessibilityEnabledFunction : public SyncExtensionFunction { 86 virtual ~SetAccessibilityEnabledFunction() {} 87 virtual bool RunImpl(); 88 DECLARE_EXTENSION_FUNCTION_NAME( 89 "experimental.accessibility.setAccessibilityEnabled") 90 }; 91 92 // API function that returns the most recent focused control. 93 class GetFocusedControlFunction : public SyncExtensionFunction { 94 virtual ~GetFocusedControlFunction() {} 95 virtual bool RunImpl(); 96 DECLARE_EXTENSION_FUNCTION_NAME( 97 "experimental.accessibility.getFocusedControl") 98 }; 99 100 #endif // CHROME_BROWSER_EXTENSIONS_EXTENSION_ACCESSIBILITY_API_H_ 101