Switch AccessibilityMode to be a bitmap

content/browser/accessibility/accessibility_mode_helper.cc

+// Copyright (c) 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 "content/browser/accessibility/accessibility_mode_helper.h"
+
+#if defined(OS_WIN)
+#include "base/command_line.h"
+#include "base/win/windows_version.h"
+#include "content/public/common/content_switches.h"
+#endif
+
+namespace content {
+
+namespace {
+
+AccessibilityMode CastToAccessibilityMode(unsigned int int_mode) {
+  AccessibilityMode mode = static_cast<AccessibilityMode>(int_mode);
+  switch (mode) {
+  case AccessibilityModeOff:
+  case AccessibilityModeComplete:
+  case AccessibilityModeEditableTextOnly:
+    return mode;
+  }
+  DCHECK(false) << "Could not convert to AccessibilityMode: " << int_mode;
+  return AccessibilityModeOff;
+}
+
+}  // namespace
+
+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);
+#if defined(OS_WIN)
+  // On Windows 8, always enable accessibility for editable text controls
+  // so we can show the virtual keyboard when one is enabled.
+  if (base::win::GetVersion() >= base::win::VERSION_WIN8 &&
+      !CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableRendererAccessibility)) {
+    if ((from & AccessibilityModeEditableTextOnly) ==
+        AccessibilityModeEditableTextOnly)
+      new_mode |= AccessibilityModeEditableTextOnly;
+  }
+#endif  // defined(OS_WIN)
+
+  return CastToAccessibilityMode(new_mode);
+}
+
+}  // namespace content