Added HttpUrlRequestListener OnResponseStarted callback.

components/cronet/android/sample/src/org/chromium/cronet_sample_apk/CronetSampleActivity.java

Index: components/cronet/android/sample/src/org/chromium/cronet_sample_apk/CronetSampleActivity.java
diff --git a/components/cronet/android/sample/src/org/chromium/cronet_sample_apk/CronetSampleActivity.java b/components/cronet/android/sample/src/org/chromium/cronet_sample_apk/CronetSampleActivity.java
index 4dd9d48a6397e8150a9447edfad969c9ef4a3558..f24fbeda59268729b32f404a31a45817046f1eb6 100644
--- a/components/cronet/android/sample/src/org/chromium/cronet_sample_apk/CronetSampleActivity.java
+++ b/components/cronet/android/sample/src/org/chromium/cronet_sample_apk/CronetSampleActivity.java
@@ -90,6 +90,12 @@ public class CronetSampleActivity extends Activity {
         }
 
         @Override
+        public void onResponseStarted(HttpUrlRequest request) {
+            Log.i(TAG, "****** Response Started, content length is "
+                    + request.getContentLength());
+        }
+
+        @Override
         public void onRequestComplete(HttpUrlRequest request) {
             Log.i(TAG, "****** Request Complete, status code is "
                     + getHttpStatusCode());