ART: Add forced garbage collection

Add ForceGarbageCollection support to the agent interface.

Add a test.

Test: m test-art-host-run-test-913-heaps
Bug: 32516268
Change-Id: Iaa97520d1b9e4b0adf088ccdf9712193c485b7c5
diff --git a/test/913-heaps/src/Main.java b/test/913-heaps/src/Main.java
new file mode 100644
index 0000000..0d1c92b
--- /dev/null
+++ b/test/913-heaps/src/Main.java
@@ -0,0 +1,52 @@
+/*
+ * 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.util.ArrayList;
+
+public class Main {
+  public static void main(String[] args) throws Exception {
+    System.loadLibrary(args[1]);
+
+    doTest();
+  }
+
+  public static void doTest() throws Exception {
+    setupGcCallback();
+
+    enableGcTracking(true);
+    run();
+    enableGcTracking(false);
+  }
+
+  private static void run() {
+    printStats();
+    forceGarbageCollection();
+    printStats();
+  }
+
+  private static void printStats() {
+      System.out.println("---");
+      int s = getGcStarts();
+      int f = getGcFinishes();
+      System.out.println((s > 0) + " " + (f > 0));
+  }
+
+  private static native void setupGcCallback();
+  private static native void enableGcTracking(boolean enable);
+  private static native int getGcStarts();
+  private static native int getGcFinishes();
+  private static native void forceGarbageCollection();
+}