Fix DumpAccessibilityEvents tests on Mac and improve test coverage

content/browser/accessibility/browser_accessibility_manager.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 166 matching lines @@
 
   // Pretend that the given node has focus, for testing only. Doesn't
   // communicate with the renderer and doesn't fire any events.
   void SetFocusLocallyForTesting(BrowserAccessibility* node);
 
   // For testing only, register a function to be called when focus changes
   // in any BrowserAccessibilityManager.
   static void SetFocusChangeCallbackForTesting(const base::Closure& callback);
 
   // Normally we avoid firing accessibility focus events when the containing
-  // native window isn't focused. However, this can lead to test flakiness
-  // because we can't control when a window loses focus, so this provides a
-  // way to disable that check for tests.
-  static void NeverSuppressFocusEventsForTesting();
+  // native window isn't focused, and we also delay some other events like
+  // live region events to improve screen reader compatibility.
+  // However, this can lead to test flakiness, so for testing, simplify
+  // this behavior and just fire all events with no delay as if the window
+  // had focus.
+  static void NeverSuppressOrDelayEventsForTesting();
 
   // Accessibility actions. All of these are implemented asynchronously
   // by sending a message to the renderer to perform the respective action
   // on the given node.  See the definition of |ui::AXActionData| for more
   // information about each of these actions.
   void Decrement(const BrowserAccessibility& node);
   void DoDefaultAction(const BrowserAccessibility& node);
   void GetImageData(const BrowserAccessibility& node,
                     const gfx::Size& max_size);
   void HitTest(const gfx::Point& point);
@@ skipping 284 matching lines @@
   int parent_node_id_from_parent_tree_;
 
   // The device scale factor for the view associated with this frame,
   // cached each time there's any update to the accessibility tree.
   float device_scale_factor_;
 
   // For testing only: If true, the manually-set device scale factor will be
   // used and it won't be updated from the delegate.
   bool use_custom_device_scale_factor_for_testing_;
 
+  // Fire all events regardless of focus and with no delay, to avoid test
+  // flakiness. See NeverSuppressOrDelayEventsForTesting() for details.
+  static bool never_suppress_or_delay_events_for_testing_;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_H_