Add host resolver rules experimental flag for Cronet

components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java

Index: components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
diff --git a/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java b/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
index 95f35eed336afe712c640f82540cbb353600e2fb..083be5ce9038ce6013383e16df568df1bd28e09f 100644
--- a/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
+++ b/components/cronet/android/test/javatests/src/org/chromium/net/CronetUrlRequestContextTest.java
@@ -20,6 +20,7 @@ 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;
@@ -1174,4 +1175,28 @@ public class CronetUrlRequestContextTest extends CronetTestBase {
         });
         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());
+    }
 }