Add a custom Robolectric testrunner.

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

Index: testing/android/junit/java/src/org/chromium/testing/local/LocalRobolectricTestRunner.java
diff --git a/testing/android/junit/java/src/org/chromium/testing/local/LocalRobolectricTestRunner.java b/testing/android/junit/java/src/org/chromium/testing/local/LocalRobolectricTestRunner.java
new file mode 100644
index 0000000000000000000000000000000000000000..8409fecab524b22a534e232da55a53d3c5d6d1d6
--- /dev/null
+++ b/testing/android/junit/java/src/org/chromium/testing/local/LocalRobolectricTestRunner.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.runners.model.InitializationError;
+
+import org.robolectric.AndroidManifest;
+import org.robolectric.DependencyResolver;
+import org.robolectric.LocalDependencyResolver;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.SdkConfig;
+import org.robolectric.annotation.Config;
+
+import java.io.File;
+
+/**
+ * A custom Robolectric Junit4 Test Runner. This test runner will load the
+ * "real" android jars from a local directory rather than use Maven to fetch
+ * them from the Maven Central repository. Additionally, it will ignore the
+ * API level written in the AndroidManifest as that can cause issues if
+ * robolectric does not support that API level.
+ */
+public class LocalRobolectricTestRunner extends RobolectricTestRunner {
+
+    public LocalRobolectricTestRunner(Class<?> testClass) throws InitializationError {
+        super(testClass);
+    }
+
+    @Override
+    protected final DependencyResolver getJarResolver() {
+        String dependencyDir = System.getProperty("robolectric.dependency.dir");
+        if (dependencyDir == null) {
+            throw new IllegalStateException("robolectric.dependency.dir not specified. Make sure"
+                    + " you are setting the robolectric.dependency.dir system property to the"
+                    + " directory containing Robolectric's runtime dependency jars.");
+        }
+        return new LocalDependencyResolver(new File(dependencyDir));
+    }
+
+    @Override
+    protected SdkConfig pickSdkVersion(AndroidManifest appManifest, Config config) {
+        // Pulling from the manifest is dangerous as the apk might target a version of
+        // android that robolectric does not yet support. We still allow the API level to
+        // be overridden with the Config annotation.
+        return config.emulateSdk() < 0 ? new SdkConfig(18) : super.pickSdkVersion(null, config);

[nyquist, 2015/03/09 22:10:54]

Could you extract 18 to a constant here and below?

[mikecase (-- gone --), 2015/03/09 23:40:40]

Done.

+    }
+
+    @Override
+    protected int pickReportedSdkVersion(Config config, AndroidManifest appManifest) {
+        return config.reportSdk() < 0 ? 18 : super.pickReportedSdkVersion(config, appManifest);
+    }
+}