Disable accessibility when VoiceOver is turned off.

(Depends on: https://codereview.chromium.org/606703003/)

BUG=251382

Review URL: https://codereview.chromium.org/602133002

Cr-Commit-Position: refs/heads/master@{#300583}

chrome/browser/chrome_browser_application_mac.mm

@@ -538,9 +538,14 @@ void SwizzleInit() {
 }
 
 - (void)accessibilitySetValue:(id)value forAttribute:(NSString*)attribute {
-  if ([attribute isEqualToString:@"AXEnhancedUserInterface"] &&
-      [value intValue] == 1) {
-    content::BrowserAccessibilityState::GetInstance()->OnScreenReaderDetected();
+  // This is an undocument attribute that's set when VoiceOver is turned on/off.
+  if ([attribute isEqualToString:@"AXEnhancedUserInterface"]) {
+    content::BrowserAccessibilityState* accessibility_state =
+        content::BrowserAccessibilityState::GetInstance();
+    if ([value intValue] == 1)
+      accessibility_state->OnScreenReaderDetected();
+    else
+      accessibility_state->DisableAccessibility();
   }
   return [super accessibilitySetValue:value forAttribute:attribute];
 }

content/renderer/accessibility/renderer_accessibility.h

@@ -60,6 +60,11 @@ class CONTENT_EXPORT RendererAccessibility : public RenderFrameObserver {
   // testing.
   virtual RendererAccessibilityType GetType() = 0;
 
+  // This can be called before deleting a RendererAccessibility instance due
+  // to the accessibility mode changing, as opposed to during frame destruction
+  // (when there'd be no point).
+  virtual void DisableAccessibility() {}
+
  protected:
   // Returns the main top-level document for this page, or NULL if there's
   // no view or frame.

content/renderer/accessibility/renderer_accessibility_complete.cc

@@ -98,6 +98,22 @@ void RendererAccessibilityComplete::FocusedNodeChanged(const WebNode& node) {
   }
 }
 
+void RendererAccessibilityComplete::DisableAccessibility() {
+  RenderView* render_view = render_frame_->GetRenderView();
+  if (!render_view)
+    return;
+
+  WebView* web_view = render_view->GetWebView();
+  if (!web_view)
+    return;
+
+  WebSettings* settings = web_view->settings();
+  if (!settings)
+    return;
+
+  settings->setAccessibilityEnabled(false);
+}
+
 void RendererAccessibilityComplete::HandleWebAccessibilityEvent(
     const blink::WebAXObject& obj, blink::WebAXEvent event) {
   HandleAXEvent(obj, AXEventFromBlink(event));

content/renderer/accessibility/renderer_accessibility_complete.h

@@ -47,6 +47,7 @@ class CONTENT_EXPORT RendererAccessibilityComplete
                                    blink::WebAXEvent event) override;
   RendererAccessibilityType GetType() override;
   void FocusedNodeChanged(const blink::WebNode& node) override;
+  virtual void DisableAccessibility() override;
 
   void HandleAXEvent(const blink::WebAXObject& obj, ui::AXEvent event);
 

content/renderer/render_frame_impl.cc

@@ -1360,6 +1360,11 @@ void RenderFrameImpl::OnSetAccessibilityMode(AccessibilityMode new_mode) {
     return;
   accessibility_mode_ = new_mode;
   if (renderer_accessibility_) {
+    // Note: this isn't called automatically by the destructor because
+    // there'd be no point in calling it in frame teardown, only if there's
+    // an accessibility mode change but the frame is persisting.
+    renderer_accessibility_->DisableAccessibility();
+
     delete renderer_accessibility_;
     renderer_accessibility_ = NULL;
   }