One accessibility tree per frame.

content/browser/accessibility/browser_accessibility_manager_android.h

 // Copyright 2013 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_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_ANDROID_H_
 #define CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_ANDROID_H_
 
 #include <stdint.h>
 
 #include "base/android/scoped_java_ref.h"
@@ skipping 196 matching lines @@
                 const base::android::JavaParamRef<jobject>& obj,
                 jint id);
 
   // Scrolls any scrollable container by about 80% of one page in the
   // given direction.
   bool Scroll(JNIEnv* env,
               const base::android::JavaParamRef<jobject>& obj,
               jint id,
               int direction);
 
+  JavaObjectWeakGlobalRef& java_ref() { return java_ref_; }
+
  protected:
   // AXTreeDelegate overrides.
   void OnAtomicUpdateFinished(
       ui::AXTree* tree,
       bool root_changed,
       const std::vector<ui::AXTreeDelegate::Change>& changes) override;
 
   bool UseRootScrollOffsetsWhenComputingBounds() override;
 
  private:
   BrowserAccessibilityAndroid* GetFromUniqueID(int32_t unique_id);
 
+   base::android::ScopedJavaLocalRef<jobject> GetJavaRefFromRootManager();
+
   // This gives BrowserAccessibilityManager::Create access to the class
   // constructor.
   friend class BrowserAccessibilityManager;
 
   // A weak reference to the Java BrowserAccessibilityManager object.
   // This avoids adding another reference to BrowserAccessibilityManager and
   // preventing garbage collection.
   // Premature garbage collection is prevented by the long-lived reference in
   // ContentViewCore.
   JavaObjectWeakGlobalRef java_ref_;
 
   // Handle a hover event from the renderer process.
   void HandleHoverEvent(BrowserAccessibility* node);
 
   // See docs for set_prune_tree_for_screen_reader, above.
   bool prune_tree_for_screen_reader_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserAccessibilityManagerAndroid);
 };
 
 bool RegisterBrowserAccessibilityManager(JNIEnv* env);
 
 }
 
 #endif  // CONTENT_BROWSER_ACCESSIBILITY_BROWSER_ACCESSIBILITY_MANAGER_ANDROID_H_