Fix Cronet compilation and test errors.

components/cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java

 // Copyright 2014 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;
 
 import android.util.Log;
 
 import org.apache.http.conn.ConnectTimeoutException;
 import org.chromium.base.CalledByNative;
@@ skipping 379 matching lines @@
     public String getContentType() {
         return mContentType;
     }
 
     public String getHeader(String name) {
         validateHeadersAvailable();
         return nativeGetHeader(mUrlRequestAdapter, name);
     }
 
     // All response headers.
+    @SuppressWarnings("unused")

[mmenke, 2014/08/25 19:46:44]

Should this be using the called by native thing?

[mef, 2014/08/25 20:26:18]

Well, it isn't really called by native.

Per discussion with clm@ (correct me if I'm wrong) my understanding of the
problem is:
1. If getAllHeaders is not unused, then proguard removes it.
2. That makes nativeGetAllHeaders also unused, so proguard also removes it.
3. When libcronet.so is loaded it tries to register implementation of
nativeGetAllHeaders, and that fails (CHECKS) as there is no java-side method
declaration (as it is removed in step 2).

I suspect that similar issue may happen if app doesn't have calls to getHeader()
either.

[mef, 2014/08/25 22:12:42]

Per discussion with clm@ this is not a fix, but just a warning suppression.
Real fix is in proguard.cfg (keep class with its native methods).

     public Map<String, List<String>> getAllHeaders() {
         validateHeadersAvailable();
         ResponseHeadersMap result = new ResponseHeadersMap();
         nativeGetAllHeaders(mUrlRequestAdapter, result);
         return result;
     }
 
     public String getUrl() {
         return mUrl;
     }
@@ skipping 265 matching lines @@
 
     private native String nativeGetHeader(long urlRequestAdapter, String name);
 
     private native void nativeGetAllHeaders(long urlRequestAdapter,
             ResponseHeadersMap headers);
 
     // Explicit class to work around JNI-generator generics confusion.
     private class ResponseHeadersMap extends HashMap<String, List<String>> {
     }
 }