Update from Google.

--
MOE_MIGRATED_REVID=85702957
diff --git a/src/main/java/com/google/devtools/build/lib/runtime/CommandEvent.java b/src/main/java/com/google/devtools/build/lib/runtime/CommandEvent.java
new file mode 100644
index 0000000..3e59dce
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/runtime/CommandEvent.java
@@ -0,0 +1,68 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// 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.
+package com.google.devtools.build.lib.runtime;
+
+import com.google.devtools.build.lib.util.BlazeClock;
+
+import java.lang.management.GarbageCollectorMXBean;
+import java.lang.management.ManagementFactory;
+import java.util.Date;
+
+/**
+ * Base class for Command events that includes some resource fields.
+ */
+public abstract class CommandEvent {
+
+  private final long eventTimeInNanos;
+  private final long eventTimeInEpochTime;
+  private final long gcTimeInMillis;
+
+  protected CommandEvent() {
+    eventTimeInNanos = BlazeClock.nanoTime();
+    eventTimeInEpochTime = new Date().getTime();
+    gcTimeInMillis = collectGcTimeInMillis();
+  }
+
+  /**
+   * Returns time spent in garbage collection since the start of the JVM process.
+   */
+  private static long collectGcTimeInMillis() {
+    long gcTime = 0;
+    for (GarbageCollectorMXBean gcBean : ManagementFactory.getGarbageCollectorMXBeans()) {
+      gcTime += gcBean.getCollectionTime();
+    }
+    return gcTime;
+  }
+
+  /**
+   * Get the time-stamp in ns for the event.
+   */
+  public long getEventTimeInNanos() {
+    return eventTimeInNanos;
+  }
+
+  /**
+   * Get the time-stamp as epoch-time for the event.
+   */
+  public long getEventTimeInEpochTime() {
+    return eventTimeInEpochTime;
+  }
+
+  /**
+   * Get the cumulative GC time for the event.
+   */
+  public long getGCTimeInMillis() {
+    return gcTimeInMillis;
+  }
+}