Makes HandleWatcher block until no longer waiting on pipe

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

Index: mojo/android/javatests/src/org/chromium/mojo/system/impl/CoreImplTest.java
diff --git a/mojo/android/javatests/src/org/chromium/mojo/system/impl/CoreImplTest.java b/mojo/android/javatests/src/org/chromium/mojo/system/impl/CoreImplTest.java
index abe7fa37d7251bbdf9eb3f68d3915e9846d755a2..97bab765d79b98086b15d0d1d2aa6eb7254d6e86 100644
--- a/mojo/android/javatests/src/org/chromium/mojo/system/impl/CoreImplTest.java
+++ b/mojo/android/javatests/src/org/chromium/mojo/system/impl/CoreImplTest.java
@@ -648,8 +648,8 @@ public class CoreImplTest extends MojoTestCase {
         assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
         assertEquals(null, asyncWaiterResult.getException());
 
-        core.getDefaultAsyncWaiter().asyncWait(handles.first, Core.HandleSignals.READABLE,
-                Core.DEADLINE_INFINITE, asyncWaiterResult);
+        Cancellable cancellable = core.getDefaultAsyncWaiter().asyncWait(handles.first,
+                Core.HandleSignals.READABLE, Core.DEADLINE_INFINITE, asyncWaiterResult);
         assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
         assertEquals(null, asyncWaiterResult.getException());
 
@@ -657,7 +657,7 @@ public class CoreImplTest extends MojoTestCase {
         assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
         assertEquals(null, asyncWaiterResult.getException());
 
-        handles.first.close();

[sky, 2014/07/23 23:37:15]

We're saying the handle must remain valid until cancel is invoked. So I changed
this.

+        cancellable.cancel();
         nativeRunLoop(RUN_LOOP_TIMEOUT_MS);
         // TODO(qsr) Re-enable when MojoWaitMany handles it correctly.
         // assertNull(asyncWaiterResult.getException());
@@ -668,56 +668,6 @@ public class CoreImplTest extends MojoTestCase {
      * Testing core {@link AsyncWaiter} implementation.
      */
     @SmallTest
-    public void testAsyncWaiterWaitingOnInvalidHandle() {
-        Core core = CoreImpl.getInstance();
-
-        // Closing the peer handle.
-        Pair<MessagePipeHandle, MessagePipeHandle> handles = core.createMessagePipe(null);
-        addHandlePairToClose(handles);
-
-        final AsyncWaiterResult asyncWaiterResult = new AsyncWaiterResult();
-        assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
-        assertEquals(null, asyncWaiterResult.getException());
-
-        handles.first.close();

[sky, 2014/07/23 23:37:14]

This test doesn't make sense as we're saying the handle passed to AsyncWait must
be valid.

[darin (slow to review), 2014/07/24 03:39:47]

Perhaps the AsyncWait function should DCHECK that the given handle is valid?

-        core.getDefaultAsyncWaiter().asyncWait(handles.first, Core.HandleSignals.READABLE,
-                Core.DEADLINE_INFINITE, asyncWaiterResult);
-        assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
-        assertEquals(null, asyncWaiterResult.getException());
-
-        nativeRunLoop(RUN_LOOP_TIMEOUT_MS);
-        assertNotNull(asyncWaiterResult.getException());
-        assertEquals(MojoResult.INVALID_ARGUMENT,
-                asyncWaiterResult.getException().getMojoResult());
-        assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
-    }
-
-    /**
-     * Testing core {@link AsyncWaiter} implementation.
-     */
-    @SmallTest
-    public void testAsyncWaiterWaitingOnDefaultInvalidHandle() {
-        Core core = CoreImpl.getInstance();
-
-        final AsyncWaiterResult asyncWaiterResult = new AsyncWaiterResult();
-        assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
-        assertEquals(null, asyncWaiterResult.getException());
-
-        core.getDefaultAsyncWaiter().asyncWait(InvalidHandle.INSTANCE, Core.HandleSignals.READABLE,

[sky, 2014/07/23 23:37:14]

Same thing here.

-                Core.DEADLINE_INFINITE, asyncWaiterResult);
-        assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
-        assertEquals(null, asyncWaiterResult.getException());
-
-        nativeRunLoop(RUN_LOOP_TIMEOUT_MS);
-        assertNotNull(asyncWaiterResult.getException());
-        assertEquals(MojoResult.INVALID_ARGUMENT, asyncWaiterResult.getException().getMojoResult());
-        assertEquals(Integer.MIN_VALUE, asyncWaiterResult.getResult());
-    }
-
-    /**
-     * Testing core {@link AsyncWaiter} implementation.
-     */
-    @SmallTest
     public void testAsyncWaiterWaitingWithTimeout() {
         Core core = CoreImpl.getInstance();