Move several annotations to annotations package.

base/android/java/src/org/chromium/base/annotations/AccessedByNative.java

 // 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.
 
-package org.chromium.base;
+package org.chromium.base.annotations;
 
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 /**
  *  @AccessedByNative is used to ensure proguard will keep this field, since it's
  *  only accessed by native.
  */
 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.CLASS)
 public @interface AccessedByNative {
     public String value() default "";
 }