ART: Add OnLoad system classloader search support

Add support for extension of the system classloader search path
during the OnLoad phase. Add test.

Bug: 34359699
Test: m test-art-host-run-test-936-search-onload
Change-Id: Ie0a5b4bb77999dfae87f955dde40b73ffe053b8e
diff --git a/test/936-search-onload/src/B.java b/test/936-search-onload/src/B.java
new file mode 100644
index 0000000..f1458c3
--- /dev/null
+++ b/test/936-search-onload/src/B.java
@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+public class B {
+}
\ No newline at end of file
diff --git a/test/936-search-onload/src/Main.java b/test/936-search-onload/src/Main.java
new file mode 100644
index 0000000..2e7a871
--- /dev/null
+++ b/test/936-search-onload/src/Main.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2017 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.util.Arrays;
+
+public class Main {
+  public static void main(String[] args) throws Exception {
+    doTest();
+  }
+
+  private static void doTest() throws Exception {
+    doTest(true, "B");
+    doTest(false, "A");
+    System.out.println("Done");
+  }
+
+  private static void doTest(boolean boot, String className) throws Exception {
+    ClassLoader expectedClassLoader;
+    if (boot) {
+      expectedClassLoader = Object.class.getClassLoader();
+    } else {
+      expectedClassLoader = ClassLoader.getSystemClassLoader();
+    }
+
+    Class<?> c = Class.forName(className, false, ClassLoader.getSystemClassLoader());
+    if (c.getClassLoader() != expectedClassLoader) {
+      throw new RuntimeException(className + "(" + boot + "): " +
+          c.getClassLoader() + " vs " + expectedClassLoader);
+    } else {
+      System.out.println(className + " was loaded with " + (boot ? "boot" : "system") +
+          " classloader");
+    }
+  }
+}