Add support for ContentViewCore helpers on Tab

content/browser/android/content_view_core_impl.cc

 // Copyright 2012 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/android/content_view_core_impl.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 238 matching lines @@
   web_contents->SetUserAgentOverride(spoofed_ua);
 
   java_bridge_dispatcher_host_ =
       new GinJavaBridgeDispatcherHost(web_contents,
                                       java_bridge_retained_object_set);
 
   InitWebContents();
 }
 
 ContentViewCoreImpl::~ContentViewCoreImpl() {
+  root_layer_->RemoveFromParent();
+
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
   java_ref_.reset();
   if (!j_obj.is_null()) {
     Java_ContentViewCore_onNativeContentViewCoreDestroyed(
         env, j_obj.obj(), reinterpret_cast<intptr_t>(this));
   }
 }
 
 base::android::ScopedJavaLocalRef<jobject>
@@ skipping 1112 matching lines @@
     return NULL;
 
   return view->GetJavaObject().Release();
 }
 
 bool RegisterContentViewCore(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content