Support audio ducking and suspension in ChromeVox

chrome/browser/extensions/api/automation_internal/automation_internal_api.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/extensions/api/automation_internal/automation_internal_api.h"
 
 #include <stdint.h>
 
 #include <vector>
 
@@ skipping 230 matching lines @@
     detail.event_type = ui::AX_EVENT_MEDIA_STOPPED_PLAYING;
     details.push_back(detail);
     AccessibilityEventReceived(details);
   }
 
  private:
   friend class content::WebContentsUserData<AutomationWebContentsObserver>;
 
   explicit AutomationWebContentsObserver(content::WebContents* web_contents)
       : content::WebContentsObserver(web_contents),
-        browser_context_(web_contents->GetBrowserContext()) {}
+        browser_context_(web_contents->GetBrowserContext()) {
+    if (web_contents->WasRecentlyAudible()) {
+      std::vector<content::AXEventNotificationDetails> details;
+      content::RenderFrameHost* rfh = web_contents->GetMainFrame();
+      if (!rfh)
+        return;
+
+      content::AXEventNotificationDetails detail;
+      detail.ax_tree_id = rfh->GetAXTreeID();
+      detail.event_type = ui::AX_EVENT_MEDIA_STARTED_PLAYING;
+      details.push_back(detail);
+      AccessibilityEventReceived(details);
+    }
+  }
 
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(AutomationWebContentsObserver);
 };
 
 ExtensionFunction::ResponseAction
 AutomationInternalEnableTabFunction::Run() {
   const AutomationInfo* automation_info = AutomationInfo::Get(extension());
   EXTENSION_FUNCTION_VALIDATE(automation_info);
@@ skipping 259 matching lines @@
   if (!error.empty()) {
     Respond(Error(error));
     return;
   }
 
   Respond(
       OneArgument(base::MakeUnique<base::FundamentalValue>(result_acc_obj_id)));
 }
 
 }  // namespace extensions