[Cronet] Separate Cronet implementation and API by package name.

components/cronet/android/api/src/org/chromium/net/CronetException.java

 // Copyright 2015 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.net;
 
 /**
  * Exception reported from UrlRequest or BidirectionalStream.
  */
 // TODO(mef): Will replace UrlRequestException soon.
 public class CronetException extends UrlRequestException {
-    CronetException(String message, Throwable cause) {
+    /**
+     * @hide only used by internal implementation.
+     */
+    public CronetException(String message, Throwable cause) {
         super(message, cause);
     }
 
-    CronetException(String message, int errorCode, int cronetInternalErrorCode) {
+    /**
+     * @hide only used by internal implementation.
+     */
+    public CronetException(String message, int errorCode, int cronetInternalErrorCode) {
         super(message, errorCode, cronetInternalErrorCode);
     }
 }