Add more fine-grained accessibility modes.

content/browser/accessibility/accessibility_mode_helper.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 "base/logging.h"
-#include "content/browser/accessibility/accessibility_mode_helper.h"
-
-namespace content {
-
-namespace {
-
-AccessibilityMode CastToAccessibilityMode(unsigned int int_mode) {
-  AccessibilityMode mode = static_cast<AccessibilityMode>(int_mode);
-  switch (mode) {
-  case AccessibilityModeOff:
-  case AccessibilityModeComplete:
-  case AccessibilityModeTreeOnly:
-    return mode;
-  }
-  DCHECK(false) << "Could not convert to AccessibilityMode: " << int_mode;
-  return AccessibilityModeOff;
-}
-
-}  // namespace
-
-AccessibilityMode GetBaseAccessibilityMode() {
-  AccessibilityMode accessibility_mode = AccessibilityModeOff;
-  return accessibility_mode;
-}
-
-AccessibilityMode AddAccessibilityModeTo(AccessibilityMode to,
-                                         AccessibilityMode mode_to_add) {
-  return CastToAccessibilityMode(to | mode_to_add);
-}
-
-AccessibilityMode RemoveAccessibilityModeFrom(
-    AccessibilityMode from,
-    AccessibilityMode mode_to_remove) {
-  unsigned int new_mode = from ^ (mode_to_remove & from);
-  return CastToAccessibilityMode(new_mode);
-}
-
-}  // namespace content