ART: Simple structural class check

Adds a simple check to class-loading when the embedded dex file in
an oat file and the dex file on the class path where we found the
class do not match.

We require that the number of methods and fields do not change, as
that will almost certainly mean that quickened and other compiled
offsets are wrong now. This is a reasonably lightweight change, but
we should investigate a full comparison including name and type of
members.

Bug: 17937814
Bug: 18708951

(cherry picked from commit 15a33b3f88546bce85dcb9d28caf200da51154d7)

Change-Id: Icb9638bebd369ab23822817f4a97c8dd8625fea5
diff --git a/test/131-structural-change/src/Main.java b/test/131-structural-change/src/Main.java
new file mode 100644
index 0000000..8dfa280
--- /dev/null
+++ b/test/131-structural-change/src/Main.java
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2015 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.io.File;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+/**
+ * Structural hazard test.
+ */
+public class Main {
+    public static void main(String[] args) {
+        new Main().run();
+    }
+
+    private void run() {
+        try {
+            Class<?> bClass = getClass().getClassLoader().loadClass("A");
+            System.out.println("Should really reach here.");
+        } catch (Exception e) {
+            e.printStackTrace(System.out);
+        }
+
+        boolean haveOatFile = hasOat();
+        boolean gotError = false;
+        try {
+            Class<?> bClass = getClass().getClassLoader().loadClass("B");
+        } catch (IncompatibleClassChangeError icce) {
+            gotError = true;
+        } catch (Exception e) {
+            e.printStackTrace(System.out);
+        }
+        if (haveOatFile ^ gotError) {
+            System.out.println("Did not get expected error.");
+        }
+        System.out.println("Done.");
+    }
+
+    static {
+        System.loadLibrary("arttest");
+    }
+
+    private native static boolean hasOat();
+}