Navigation buttons should not enable if user can not navigate

content/shell/browser/shell_android.cc

 // 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.
 
 #include "content/shell/browser/shell.h"
 
 #include <jni.h>
 
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 18 matching lines @@
 }
 
 void Shell::PlatformCleanUp() {
   JNIEnv* env = AttachCurrentThread();
   if (java_object_.is_null())
     return;
   Java_Shell_onNativeDestroyed(env, java_object_.obj());
 }
 
 void Shell::PlatformEnableUIControl(UIControl control, bool is_enabled) {
+  JNIEnv* env = AttachCurrentThread();
+  if (java_object_.is_null())
+    return;
+  Java_Shell_enableUiControl(env, java_object_.obj(), control, is_enabled);
 }
 
 void Shell::PlatformSetAddressBarURL(const GURL& url) {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jstring> j_url = ConvertUTF8ToJavaString(env, url.spec());
   Java_Shell_onUpdateUrl(env, java_object_.obj(), j_url.obj());
 }
 
 void Shell::PlatformSetIsLoading(bool loading) {
   JNIEnv* env = AttachCurrentThread();
@@ skipping 51 matching lines @@
   return RegisterNativesImpl(env);
 }
 
 // static
 void CloseShell(JNIEnv* env, jclass clazz, jlong shellPtr) {
   Shell* shell = reinterpret_cast<Shell*>(shellPtr);
   shell->Close();
 }
 
 }  // namespace content