Add a custom Robolectric testrunner.

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

Index: testing/android/junit/java/src/org/chromium/testing/local/ChromeRobolectricTestRunner.java
diff --git a/testing/android/junit/java/src/org/chromium/testing/local/ChromeRobolectricTestRunner.java b/testing/android/junit/java/src/org/chromium/testing/local/ChromeRobolectricTestRunner.java
new file mode 100644
index 0000000000000000000000000000000000000000..a3ba37dd4a7ffedfb77fdc9a45fa75e0ad638eb1
--- /dev/null
+++ b/testing/android/junit/java/src/org/chromium/testing/local/ChromeRobolectricTestRunner.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 Robolectric Junit4 Test Runner customized to load the "real" android jars

[jbudorick, 2015/02/27 15:12:48]

nit: Shorten the first sentence & go into a bit more detail in subsequent
sentences.

[mikecase (-- gone --), 2015/03/02 19:08:38]

Done.

+ * from Chromium directory rather than use Maven to fetch them from the
+ * Maven Central repository.
+ */
+public class ChromeRobolectricTestRunner extends RobolectricTestRunner {
+
+    public ChromeRobolectricTestRunner(Class<?> testClass) throws InitializationError {
+        super(testClass);
+    }
+
+    @Override
+    protected final DependencyResolver getJarResolver() {
+        File dependencyDir;
+        if (System.getProperty("robolectric.dependency.dir") == 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.");
+        } else {
+            dependencyDir = new File(System.getProperty("robolectric.dependency.dir"));
+        }
+        return new LocalDependencyResolver(dependencyDir);
+    }
+
+    @Override
+    protected SdkConfig pickSdkVersion(AndroidManifest appManifest, Config config) {
+        // Pulling from the manifest is dangerous as Chrome 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);

[jbudorick, 2015/02/27 15:12:48]

Robolectric has the android 5.0 jar up in Maven:
http://search.maven.org/#search%7Cgav%7C1%7Cg%3A%22org.robolectric%22%20AND%2...

Should we add that to third_party/robolectric/lib s.t. this can support SDK
level 21?

[mikecase (-- gone --), 2015/03/02 19:08:38]

The robolectric prebuilt doesn't exist yet that supports SDK 21. Once that is
added, we will need to add robolectric-prebuild-3.0, and android-all-5.0 to the
robolectric/libs, and change the SDK level to 21. 

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