Scope and clean up uses of AccessibilityMode.

content/common/accessibility_mode.h

+// Copyright 2017 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_COMMON_ACCESSIBILITY_MODE_ENUMS_H_
+#define CONTENT_COMMON_ACCESSIBILITY_MODE_ENUMS_H_
+
+namespace content {
+
+class AccessibilityMode {
+ public:
+  // Native accessibility APIs, specific to each platform, are enabled.
+  // When this mode is set that indicates the presence of a third-party
+  // client accessing Chrome via accessibility APIs. However, unless one
+  // of the modes below is set, the contents of web pages will not be
+  // accessible.
+  static constexpr uint32_t kNativeAPIs = 1 << 0;
+
+  // The renderer process will generate an accessibility tree containing
+  // basic information about all nodes, including role, name, value,
+  // state, and location. This is the minimum mode required in order for
+  // web contents to be accessible, and the remaining modes are meaningless
+  // unless this one is set.
+  //
+  // Note that sometimes this mode will be set when kNativeAPI is not, when the
+  // content layer embedder is providing accessibility support via some other
+  // mechanism other than what's implemented in content/browser.
+  static constexpr uint32_t kWebContents = 1 << 1;
+
+  // The accessibility tree will contain inline text boxes, which are
+  // necessary to expose information about line breaks and word boundaries.
+  // Without this mode, you can retrieve the plaintext value of a text field
+  // but not the information about how it's broken down into lines.
+  //
+  // Note that when this mode is off it's still possible to request inline
+  // text boxes for a specific node on-demand, asynchronously.
+  static constexpr uint32_t kInlineTextBoxes = 1 << 2;
+
+  // The accessibility tree will contain extra accessibility
+  // attributes typically only needed by screen readers and other
+  // assistive technology for blind users. Examples include text style
+  // attributes, table cell information, live region properties, range
+  // values, and relationship attributes.
+  static constexpr uint32_t kScreenReader = 1 << 3;
+
+  // The accessibility tree will contain the HTML tag name and HTML attributes
+  // for all accessibility nodes that come from web content.
+  static constexpr uint32_t kHTML = 1 << 4;
+
+  constexpr AccessibilityMode() : flags_(0) {}
+  constexpr AccessibilityMode(uint32_t flags) : flags_(flags) {}
+
+  bool has_mode(uint32_t flag) const { return (flags_ & flag) > 0; }
+
+  void set_mode(uint32_t flag, bool value) {
+    flags_ = value ? (flags_ | flag) : (flags_ & ~flag);
+  }
+
+  uint32_t mode() const { return flags_; }
+
+  bool operator==(AccessibilityMode rhs) const {
+    if (flags_ == rhs.flags_)
+      return true;
+    return false;
+  }
+
+  bool is_mode_off() const { return flags_ == 0; }
+
+  bool operator!=(AccessibilityMode rhs) const { return !(*this == rhs); }
+
+  AccessibilityMode& operator|=(const AccessibilityMode& rhs) {
+    flags_ |= rhs.flags_;
+    return *this;
+  }
+
+ private:
+  uint32_t flags_;
+};
+
+static constexpr AccessibilityMode kAccessibilityModeWebContentsOnly(
+    AccessibilityMode::kWebContents | AccessibilityMode::kInlineTextBoxes |
+    AccessibilityMode::kScreenReader |
+    AccessibilityMode::kHTML);
+
+static constexpr AccessibilityMode kAccessibilityModeComplete(
+    AccessibilityMode::kNativeAPIs | AccessibilityMode::kWebContents |
+    AccessibilityMode::kInlineTextBoxes |
+    AccessibilityMode::kScreenReader |
+    AccessibilityMode::kHTML);
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_ACCESSIBILITY_MODE_ENUMS_H_