Switch AccessibilityMode to be a bitmap

content/browser/accessibility/browser_accessibility_state_impl.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_STATE_IMPL_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_STATE_IMPL_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 30 matching lines @@
   static BrowserAccessibilityStateImpl* GetInstance();
 
   virtual void EnableAccessibility() OVERRIDE;
   virtual void DisableAccessibility() OVERRIDE;
   virtual void OnScreenReaderDetected() OVERRIDE;
   virtual bool IsAccessibleBrowser() OVERRIDE;
   virtual void AddHistogramCallback(base::Closure callback) OVERRIDE;
 
   virtual void UpdateHistogramsForTesting() OVERRIDE;
 
-  AccessibilityMode accessibility_mode() const { return accessibility_mode_; };
-  void SetAccessibilityMode(AccessibilityMode mode);
+  unsigned int accessibility_mode() const { return accessibility_mode_; };
+
+  // Adds the given accessibility mode to the current accessibility mode bitmap.
+  void AddAccessibilityMode(AccessibilityMode mode);
+
+  // Removes the given accessibility mode from the current accessibility mode
+  // bitmap, managing the bits that are shared with other modes such that a
+  // bit will only be turned off when all modes that depend on it have been
+  // removed.
+  void RemoveAccessibilityMode(AccessibilityMode mode);
 
  private:
   friend class base::RefCountedThreadSafe<BrowserAccessibilityStateImpl>;
   friend struct DefaultSingletonTraits<BrowserAccessibilityStateImpl>;
 
   // Called a short while after startup to allow time for the accessibility
   // state to be determined. Updates histograms with the current state.
   void UpdateHistograms();
 
   // Leaky singleton, destructor generally won't be called.
   virtual ~BrowserAccessibilityStateImpl();
 
   void UpdatePlatformSpecificHistograms();
 
-  AccessibilityMode accessibility_mode_;
+  // Updates the accessibility mode of all render widgets, including swapped out
+  // ones. |add| specifies whether the mode should be added or removed.
+  void AddOrRemoveFromRenderWidgets(AccessibilityMode mode, bool add);
+
+  unsigned int accessibility_mode_;
 
   std::vector<base::Closure> histogram_callbacks_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityStateImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_STATE_IMPL_H_