Mojo: Armed Watchers

mojo/android/javatests/src/org/chromium/mojo/system/impl/WatcherImplTest.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.mojo.system.impl;
 
 import android.support.test.filters.SmallTest;
 
 import org.chromium.mojo.MojoTestCase;
 import org.chromium.mojo.system.Core;
@@ skipping 50 matching lines @@
         super.tearDown();
     }
 
     private void addHandlePairToClose(Pair<? extends Handle, ? extends Handle> handles) {
         mHandlesToClose.add(handles.first);
         mHandlesToClose.add(handles.second);
     }
 
     private static class WatcherResult implements Callback {
         private int mResult = Integer.MIN_VALUE;
+        private MessagePipeHandle mReadPipe;
+
+        /**
+         * @param readPipe A MessagePipeHandle to read from when onResult triggers success.
+         */
+        public WatcherResult(MessagePipeHandle readPipe) {
+            mReadPipe = readPipe;
+        }
+        public WatcherResult() {
+            this(null);
+        }
 
         /**
          * @see Callback#onResult(int)
          */
         @Override
         public void onResult(int result) {
             this.mResult = result;
+
+            if (result == MojoResult.OK && mReadPipe != null) {
+                mReadPipe.readMessage(
+                        null, 0, MessagePipeHandle.ReadFlags.none().setMayDiscard(true));
+            }
         }
 
         /**
          * @return the result
          */
         public int getResult() {
             return mResult;
         }
     }
 
     /**
      * Testing {@link Watcher} implementation.
      */
     @SmallTest
     public void testCorrectResult() {
         // Checking a correct result.
         Pair<MessagePipeHandle, MessagePipeHandle> handles = mCore.createMessagePipe(null);
         addHandlePairToClose(handles);
-        final WatcherResult watcherResult = new WatcherResult();
+        final WatcherResult watcherResult = new WatcherResult(handles.first);
         assertEquals(Integer.MIN_VALUE, watcherResult.getResult());
 
         mWatcher.start(handles.first, Core.HandleSignals.READABLE, watcherResult);
         assertEquals(Integer.MIN_VALUE, watcherResult.getResult());
 
         handles.second.writeMessage(
                 ByteBuffer.allocateDirect(1), null, MessagePipeHandle.WriteFlags.NONE);
         runLoopUntilIdle();
         assertEquals(MojoResult.OK, watcherResult.getResult());
     }
@@ skipping 123 matching lines @@
         assertEquals(Integer.MIN_VALUE, watcherResult.getResult());
 
         mWatcher.start(handles.first, Core.HandleSignals.READABLE, watcherResult);
         assertEquals(Integer.MIN_VALUE, watcherResult.getResult());
         mWatcher.cancel();
 
         runLoopUntilIdle();
         assertEquals(Integer.MIN_VALUE, watcherResult.getResult());
     }
 }