Revert of Migrate accessibility from RenderView to RenderFrame.

content/common/view_message_enums.h

Index: content/common/view_message_enums.h
diff --git a/content/common/view_message_enums.h b/content/common/view_message_enums.h
index 4d3d193ebcfe27ca9b54a3667f38ff5bd9d4ce08..37179e826315bd9649a24c11c75b0fed943ec634 100644
--- a/content/common/view_message_enums.h
+++ b/content/common/view_message_enums.h
@@ -22,4 +22,34 @@
   }
 };
 
+// Note: keep enums in content/browser/resources/accessibility/accessibility.js
+// in sync with these two enums.
+enum AccessibilityModeFlag {
+  // Accessibility updates are processed to create platform trees and events are
+  // passed to platform APIs in the browser.
+  AccessibilityModeFlagPlatform = 1 << 0,
+
+  // Accessibility is on, and the full tree is computed. If this flag is off,
+  // only limited information about editable text nodes is sent to the browser
+  // process. Useful for implementing limited UIA on tablets.
+  AccessibilityModeFlagFullTree = 1 << 1,
+};
+
+enum AccessibilityMode {
+  // All accessibility is off.
+  AccessibilityModeOff = 0,
+
+  // Renderer accessibility is on, platform APIs are called, but only limited
+  // information is available (see AccessibilityModeFlagEditableTextOnly).
+  AccessibilityModeEditableTextOnly = AccessibilityModeFlagPlatform,
+
+  // Renderer accessibility is on, and platform APIs are called.
+  AccessibilityModeComplete =
+      AccessibilityModeFlagPlatform | AccessibilityModeFlagFullTree,
+
+  // Renderer accessibility is on, and events are passed to any extensions
+  // requesting automation, but not to platform accessibility.
+  AccessibilityModeTreeOnly = AccessibilityModeFlagFullTree,
+};
+
 #endif  // CONTENT_COMMON_VIEW_MESSAGES_ENUMS_H_