ChromeVox: Disable following a11y events after screen off alert is received

chrome/browser/ui/ash/chrome_shell_delegate.cc

Index: chrome/browser/ui/ash/chrome_shell_delegate.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.cc b/chrome/browser/ui/ash/chrome_shell_delegate.cc
index 8eb1cba9e40d325810a6b7e0d54c1c394832878a..b54479c9ebbd84d4514dac678ea4da578deaf053 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.cc
@@ -277,6 +277,7 @@ class AccessibilityDelegateImpl : public ash::AccessibilityDelegate {
 
   void TriggerAccessibilityAlert(ash::AccessibilityAlert alert) override {
     Profile* profile = ProfileManager::GetActiveUserProfile();
+    bool screen_off_alert = false;
     if (profile) {
       int msg = 0;
       switch (alert) {
@@ -287,9 +288,11 @@ class AccessibilityDelegateImpl : public ash::AccessibilityDelegate {
           msg = IDS_A11Y_ALERT_CAPS_OFF;
           break;
         case ash::A11Y_ALERT_SCREEN_ON:
+          SetAutomationManagerEnabled(profile, true);
           msg = IDS_A11Y_ALERT_SCREEN_ON;
           break;
         case ash::A11Y_ALERT_SCREEN_OFF:
+          screen_off_alert = true;
           msg = IDS_A11Y_ALERT_SCREEN_OFF;
           break;
         case ash::A11Y_ALERT_WINDOW_NEEDED:
@@ -306,6 +309,8 @@ class AccessibilityDelegateImpl : public ash::AccessibilityDelegate {
       if (msg) {
         AutomationManagerAura::GetInstance()->HandleAlert(
             profile, l10n_util::GetStringUTF8(msg));
+        if (screen_off_alert)

[James Cook, 2017/02/04 00:00:38]

Can you just check alert == ash::A11Y_ALERT_SCREEN_OFF instead of introducing a
new local variable?

Also, this code needs comments about why you are doing this. It's not obvious to
me from reading the code why you are turning things on and off.

[Qiang(Joe) Xu, 2017/02/06 03:13:57]

Done.

+          SetAutomationManagerEnabled(profile, false);
       }
     }
   }
@@ -339,6 +344,12 @@ class AccessibilityDelegateImpl : public ash::AccessibilityDelegate {
   }
 
  private:
+  void SetAutomationManagerEnabled(content::BrowserContext* context,
+                                   bool enabled) {
+    AutomationManagerAura* manager = AutomationManagerAura::GetInstance();

[James Cook, 2017/02/04 00:00:38]

optional: DCHECK(context); so the reader knows it cannot be null.

[Qiang(Joe) Xu, 2017/02/06 03:13:57]

Done.

+    enabled ? manager->Enable(context) : manager->Disable();

[James Cook, 2017/02/04 00:00:38]

Use if (enabled) not a trigraph.

[Qiang(Joe) Xu, 2017/02/06 03:13:57]

Done.

+  }
+
   DISALLOW_COPY_AND_ASSIGN(AccessibilityDelegateImpl);
 };