Revert of Revert of Migrate accessibility from RenderView to RenderFrame.

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index b39553efd847b4b740a2c7e62c1f8c62a7a371c8..b16330626f7ce925b91c97466f6b85b02f14ef71 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -222,6 +222,18 @@
   virtual void SetUserAgentOverride(const std::string& override) = 0;
   virtual const std::string& GetUserAgentOverride() const = 0;
 
+  // Enable the accessibility tree for this WebContents in the renderer,
+  // but don't enable creating a native accessibility tree on the browser
+  // side.
+  virtual void EnableTreeOnlyAccessibilityMode() = 0;
+
+  // Returns true only if "tree only" accessibility mode is on.
+  virtual bool IsTreeOnlyAccessibilityModeForTesting() const = 0;
+
+  // Returns true only if complete accessibility mode is on, meaning there's
+  // both renderer accessibility, and a native browser accessibility tree.
+  virtual bool IsFullAccessibilityModeForTesting() const = 0;
+
 #if defined(OS_WIN)
   virtual void SetParentNativeViewAccessible(
       gfx::NativeViewAccessible accessible_parent) = 0;