Merge pull request #6446 from electron/accessibility-api

Add API for Chrome's accessibility support state

atom/browser/api/atom_api_app.cc

@@ -32,6 +32,7 @@
 #include "base/strings/string_util.h"
 #include "brightray/browser/brightray_paths.h"
 #include "chrome/common/chrome_paths.h"
+#include "content/public/browser/browser_accessibility_state.h"
 #include "content/public/browser/client_certificate_delegate.h"
 #include "content/public/browser/gpu_data_manager.h"
 #include "content/public/browser/render_frame_host.h"
@@ -281,6 +282,10 @@ void App::OnFinishLaunching() {
   Emit("ready");
 }
 
+void App::OnAccessibilitySupportChanged() {
+  Emit("accessibility-support-changed", IsAccessibilitySupportEnabled());
+}
+
 #if defined(OS_MACOSX)
 void App::OnContinueUserActivity(
     bool* prevent_default,
@@ -486,6 +491,11 @@ void App::DisableHardwareAcceleration(mate::Arguments* args) {
   content::GpuDataManager::GetInstance()->DisableHardwareAcceleration();
 }
 
+bool App::IsAccessibilitySupportEnabled() {
+  auto ax_state = content::BrowserAccessibilityState::GetInstance();
+  return ax_state->IsAccessibleBrowser();
+}
+
 #if defined(USE_NSS_CERTS)
 void App::ImportCertificate(
     const base::DictionaryValue& options,
@@ -578,6 +588,8 @@ void App::BuildPrototype(
       .SetMethod("makeSingleInstance", &App::MakeSingleInstance)
       .SetMethod("releaseSingleInstance", &App::ReleaseSingleInstance)
       .SetMethod("relaunch", &App::Relaunch)
+      .SetMethod("isAccessibilitySupportEnabled",
+                 &App::IsAccessibilitySupportEnabled)
       .SetMethod("disableHardwareAcceleration",
                  &App::DisableHardwareAcceleration);
 }

atom/browser/api/atom_api_app.h

@@ -72,6 +72,7 @@ class App : public AtomBrowserClient::Delegate,
   void OnFinishLaunching() override;
   void OnLogin(LoginHandler* login_handler,
                const base::DictionaryValue& request_details) override;
+  void OnAccessibilitySupportChanged() override;
 #if defined(OS_MACOSX)
   void OnContinueUserActivity(
       bool* prevent_default,
@@ -113,6 +114,7 @@ class App : public AtomBrowserClient::Delegate,
   void ReleaseSingleInstance();
   bool Relaunch(mate::Arguments* args);
   void DisableHardwareAcceleration(mate::Arguments* args);
+  bool IsAccessibilitySupportEnabled();
 #if defined(USE_NSS_CERTS)
   void ImportCertificate(const base::DictionaryValue& options,
                          const net::CompletionCallback& callback);

atom/browser/browser.cc

@@ -155,6 +155,12 @@ void Browser::DidFinishLaunching() {
   FOR_EACH_OBSERVER(BrowserObserver, observers_, OnFinishLaunching());
 }
 
+void Browser::OnAccessibilitySupportChanged() {
+  FOR_EACH_OBSERVER(BrowserObserver,
+                    observers_,
+                    OnAccessibilitySupportChanged());
+}
+
 void Browser::RequestLogin(
     LoginHandler* login_handler,
     std::unique_ptr<base::DictionaryValue> request_details) {

atom/browser/browser.h

@@ -185,6 +185,8 @@ class Browser : public WindowListObserver {
   void WillFinishLaunching();
   void DidFinishLaunching();
 
+  void OnAccessibilitySupportChanged();
+
   // Request basic auth login.
   void RequestLogin(LoginHandler* login_handler,
                     std::unique_ptr<base::DictionaryValue> request_details);

atom/browser/browser_observer.h

@@ -52,6 +52,9 @@ class BrowserObserver {
   virtual void OnLogin(LoginHandler* login_handler,
                        const base::DictionaryValue& request_details) {}
 
+  // The browser's accessibility suppport has changed.
+  virtual void OnAccessibilitySupportChanged() {}
+
 #if defined(OS_MACOSX)
   // The browser wants to resume a user activity via handoff. (macOS only)
   virtual void OnContinueUserActivity(

atom/browser/mac/atom_application.mm

@@ -83,6 +83,8 @@
   } else {
     ax_state->DisableAccessibility();
   }
+
+  atom::Browser::Get()->OnAccessibilitySupportChanged();
 }
 
 @end

atom/browser/native_window_views_win.cc

@@ -2,6 +2,7 @@
 // Use of this source code is governed by the MIT license that can be
 // found in the LICENSE file.
 
+#include "atom/browser/browser.h"
 #include "atom/browser/native_window_views.h"
 #include "content/public/browser/browser_accessibility_state.h"
 
@@ -98,6 +99,7 @@ bool NativeWindowViews::PreHandleMSG(
         if (axState && !axState->IsAccessibleBrowser()) {
           axState->OnScreenReaderDetected();
           enabled_a11y_support_ = true;
+          Browser::Get()->OnAccessibilitySupportChanged();
         }
       }
 

docs/api/app.md

@@ -259,6 +259,19 @@ app.on('login', (event, webContents, request, authInfo, callback) => {
 
 Emitted when the gpu process crashes.
 
+### Event: 'accessibility-support-changed' _macOS_ _Windows_
+
+Returns:
+
+* `event` Event
+* `accessibilitySupportEnabled` Boolean - `true` when Chrome's accessibility
+  support is enabled, `false` otherwise.
+
+Emitted when Chrome's accessibility support changes. This event fires when
+assistive technologies, such as screen readers, are enabled or disabled.
+See https://www.chromium.org/developers/design-documents/accessibility for more
+details.
+
 ## Methods
 
 The `app` object has the following methods:
@@ -625,6 +638,14 @@ Return an Object with the login item settings of the app.
 
 Set the app's login item settings.
 
+### `app.isAccessibilitySupportEnabled()` _macOS_ _Windows_
+
+Returns a `Boolean`, `true` if Chrome's accessibility support is enabled,
+`false` otherwise. This API will return `true` if the use of assistive
+technologies, such as screen readers, has been detected. See
+https://www.chromium.org/developers/design-documents/accessibility for more
+details.
+
 ### `app.commandLine.appendSwitch(switch[, value])`
 
 Append a switch (with optional `value`) to Chromium's command line.

spec/api-app-spec.js

@@ -339,4 +339,10 @@ describe('app module', function () {
       })
     })
   })
+
+  describe('isAccessibilitySupportEnabled API', function () {
+    it('returns whether the Chrome has accessibility APIs enabled', function () {
+      assert.equal(typeof app.isAccessibilitySupportEnabled(), 'boolean')
+    })
+  })
 })