ART: Add GetClassSignature

Add support to retrieve the signature of a JNI class.

Add a test.

Bug: 31684578
Test: m test-art-host-run-test-912-classes
Change-Id: I1cf946996f9089cb5d41e93b4f1064193e9d6350
diff --git a/test/912-classes/src/Main.java b/test/912-classes/src/Main.java
new file mode 100644
index 0000000..025584e
--- /dev/null
+++ b/test/912-classes/src/Main.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Proxy;
+import java.util.Arrays;
+
+public class Main {
+  public static void main(String[] args) throws Exception {
+    System.loadLibrary(args[1]);
+
+    doTest();
+  }
+
+  public static void doTest() throws Exception {
+    testClass("java.lang.Object");
+    testClass("java.lang.String");
+    testClass("java.lang.Math");
+    testClass("java.util.List");
+
+    testClass(getProxyClass());
+
+    testClass(int.class);
+    testClass(double[].class);
+  }
+
+  private static Class<?> proxyClass = null;
+
+  private static Class<?> getProxyClass() throws Exception {
+    if (proxyClass != null) {
+      return proxyClass;
+    }
+
+    proxyClass = Proxy.getProxyClass(Main.class.getClassLoader(), new Class[] { Runnable.class });
+    return proxyClass;
+  }
+
+  private static void testClass(String className) throws Exception {
+    Class<?> base = Class.forName(className);
+    testClass(base);
+  }
+
+  private static void testClass(Class<?> base) throws Exception {
+    String[] result = getClassSignature(base);
+    System.out.println(Arrays.toString(result));
+  }
+
+  private static native String[] getClassSignature(Class<?> c);
+}