[Cronet] Adds header field location test

BUG=398997

Review URL: https://codereview.chromium.org/885783008

Cr-Commit-Position: refs/heads/master@{#315073}

components/cronet/android/test/javatests/src/org/chromium/cronet_test_apk/urlconnection/CronetHttpURLConnectionTest.java

@@ -544,6 +544,7 @@ public class CronetHttpURLConnectionTest extends CronetTestBase {
         connection.setInstanceFollowRedirects(false);
         assertEquals(302, connection.getResponseCode());
         assertEquals("Found", connection.getResponseMessage());
+        assertEquals("/success.txt", connection.getHeaderField("Location"));
         assertEquals(NativeTestServer.getFileURL("/redirect.html"),
                 connection.getURL().toString());
         connection.disconnect();
@@ -559,6 +560,7 @@ public class CronetHttpURLConnectionTest extends CronetTestBase {
                 (HttpURLConnection) url.openConnection();
         assertEquals(302, connection.getResponseCode());
         assertEquals("Found", connection.getResponseMessage());
+        assertEquals("/success.txt", connection.getHeaderField("Location"));
         assertEquals(NativeTestServer.getFileURL("/redirect.html"),
                 connection.getURL().toString());
         connection.disconnect();