Add json output to Junit tests.

testing/android/junit/java/src/org/chromium/testing/local/JsonListener.java

Index: testing/android/junit/java/src/org/chromium/testing/local/JsonListener.java
diff --git a/testing/android/junit/java/src/org/chromium/testing/local/JsonListener.java b/testing/android/junit/java/src/org/chromium/testing/local/JsonListener.java
new file mode 100644
index 0000000000000000000000000000000000000000..3d501b3b18b4b41366016e61af7b7c746f77b946
--- /dev/null
+++ b/testing/android/junit/java/src/org/chromium/testing/local/JsonListener.java
@@ -0,0 +1,54 @@
+// Copyright 2015 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.testing.local;
+
+import org.junit.runner.Description;
+import org.junit.runner.Result;
+import org.junit.runner.notification.Failure;
+import org.junit.runner.notification.RunListener;
+
+/** A json RunListener that creates a Json file with test run information.
+ */
+public class JsonListener extends RunListener {
+
+    private final JsonLogger mJsonLogger;
+    private long mTestStartTimeMillis;
+    private boolean mCurrentTestPassed;
+
+    public JsonListener(JsonLogger jsonLogger) {
+        mJsonLogger = jsonLogger;
+    }
+
+    /** Called after all tests run.
+     */
+    @Override
+    public void testRunFinished(Result r) throws Exception {
+        mJsonLogger.writeJsonToFile();
+    }
+
+    /** Called when a test is about to start.
+     */
+    @Override
+    public void testStarted(Description d) throws Exception {
+        mCurrentTestPassed = true;
+        mTestStartTimeMillis = System.currentTimeMillis();
+    }
+
+    /** Called when a test has just finished.
+     */
+    @Override
+    public void testFinished(Description d) throws Exception {
+        long testElapsedTimeMillis = System.currentTimeMillis() - mTestStartTimeMillis;
+        mJsonLogger.addTestResultInfo(d, mCurrentTestPassed, testElapsedTimeMillis);
+    }
+
+    /** Called when a test fails.
+     */
+    @Override
+    public void testFailure(Failure f) throws Exception {
+        mCurrentTestPassed = false;
+    }
+}
+