Revert of Straightens outs DEPS in mojo/common

mojo/common/handle_watcher.h

Index: mojo/common/handle_watcher.h
diff --git a/mojo/common/handle_watcher.h b/mojo/common/handle_watcher.h
new file mode 100644
index 0000000000000000000000000000000000000000..9056ec4bbba179ab52d3c9661ea0a6725f070bb1
--- /dev/null
+++ b/mojo/common/handle_watcher.h
@@ -0,0 +1,64 @@
+// Copyright 2013 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.
+
+#ifndef MOJO_COMMON_HANDLE_WATCHER_H_
+#define MOJO_COMMON_HANDLE_WATCHER_H_
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/run_loop.h"
+#include "mojo/common/mojo_common_export.h"
+#include "third_party/mojo/src/mojo/public/cpp/system/core.h"
+
+namespace base {
+class Thread;
+}
+
+namespace mojo {
+namespace common {
+namespace test {
+class HandleWatcherTest;
+}
+
+// HandleWatcher is used to asynchronously wait on a handle and notify a Closure
+// when the handle is ready, or the deadline has expired.
+class MOJO_COMMON_EXPORT HandleWatcher {
+ public:
+  HandleWatcher();
+
+  // The destructor implicitly stops listening. See Stop() for details.
+  ~HandleWatcher();
+
+  // Starts listening for |handle|. This implicitly invokes Stop(). In other
+  // words, Start() performs one asynchronous watch at a time. It is ok to call
+  // Start() multiple times, but it cancels any existing watches. |callback| is
+  // notified when the handle is ready, invalid or deadline has passed and is
+  // notified on the thread Start() was invoked on. If the current thread exits
+  // before the handle is ready, then |callback| is invoked with a result of
+  // MOJO_RESULT_ABORTED.
+  void Start(const Handle& handle,
+             MojoHandleSignals handle_signals,
+             MojoDeadline deadline,
+             const base::Callback<void(MojoResult)>& callback);
+
+  // Stops listening. Does nothing if not in the process of listening. Blocks
+  // until no longer listening on the handle.
+  void Stop();
+
+ private:
+  class StateBase;
+  class SameThreadWatchingState;
+  class SecondaryThreadWatchingState;
+
+  // If non-NULL Start() has been invoked.
+  scoped_ptr<StateBase> state_;
+
+  DISALLOW_COPY_AND_ASSIGN(HandleWatcher);
+};
+
+}  // namespace common
+}  // namespace mojo
+
+#endif  // MOJO_COMMON_HANDLE_WATCHER_H_