Add host resolver rules experimental flag for Cronet

components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.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 static org.chromium.base.CollectionUtil.newHashSet;
 
 import android.content.Context;
 import android.content.ContextWrapper;
 import android.os.ConditionVariable;
 import android.os.Handler;
 import android.os.Looper;
 import android.test.suitebuilder.annotation.SmallTest;
 
 import org.chromium.base.PathUtils;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.FlakyTest;
 import org.chromium.net.CronetEngine.UrlRequestInfo;
 import org.chromium.net.TestUrlRequestCallback.ResponseStep;
 import org.chromium.net.test.EmbeddedTestServer;
+import org.json.JSONObject;
 
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileReader;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.NoSuchElementException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
@@ skipping 1134 matching lines @@
                         cronetEngine.shutdown();
                     }
                 }.start();
                 otherThreadDone.block();
                 builder.build().shutdown();
                 uiThreadDone.open();
             }
         });
         assertTrue(uiThreadDone.block(1000));
     }
+
+    @SmallTest
+    @Feature({"Cronet"})
+    public void testHostResolverRules() throws Exception {
+        String resolverTestHostname = "some-weird-hostname";
+        // Split mUrl into "http:", "", hostname, relative URL
+        String[] testUrlParts = mUrl.split("/");

[pauljensen, 2016/06/10 14:19:37]

this is pretty confusing, why not:
URL testUrl = new URL(mUrl);
....
testUrl.getHost()
....
testUrl.getPath()

[mgersh, 2016/06/29 17:43:31]

I didn't know that existed. Done.

+        CronetEngine.Builder cronetEngineBuilder = new CronetEngine.Builder(getContext());
+        JSONObject hostResolverRules = new JSONObject().put(
+                "host_resolver_rules", "MAP " + resolverTestHostname + " " + testUrlParts[2]);
+        JSONObject experimentalOptions =
+                new JSONObject().put("HostResolverRules", hostResolverRules);
+        cronetEngineBuilder.setExperimentalOptions(experimentalOptions.toString());
+
+        mTestFramework =
+                startCronetTestFrameworkWithUrlAndCronetEngineBuilder(null, cronetEngineBuilder);
+        TestUrlRequestCallback callback = new TestUrlRequestCallback();
+        UrlRequest.Builder urlRequestBuilder =
+                new UrlRequest.Builder("http://" + resolverTestHostname + "/" + testUrlParts[3],

[pauljensen, 2016/06/10 14:19:37]

nit: maybe build the URL with:
         new URL("http", resolverHostname, testUrl.getPath())

[mgersh, 2016/06/29 17:43:31]

Done.

+                        callback, callback.getExecutor(), mTestFramework.mCronetEngine);
+        urlRequestBuilder.build().start();
+        callback.blockForDone();
+        assertEquals(200, callback.mResponseInfo.getHttpStatusCode());
+    }
 }