Adds Mojo IDL.

third_party/WebKit/Source/core/mojo/MojoWatcher.h

Index: third_party/WebKit/Source/core/mojo/MojoWatcher.h
diff --git a/third_party/WebKit/Source/core/mojo/MojoWatcher.h b/third_party/WebKit/Source/core/mojo/MojoWatcher.h
new file mode 100644
index 0000000000000000000000000000000000000000..8cdf1ffd9605995e7680e0720f5fc81ae9b6377d
--- /dev/null
+++ b/third_party/WebKit/Source/core/mojo/MojoWatcher.h
@@ -0,0 +1,62 @@
+// Copyright 2017 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 MojoWatcher_h
+#define MojoWatcher_h
+
+#include "bindings/core/v8/ActiveScriptWrappable.h"
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "bindings/core/v8/TraceWrapperMember.h"
+#include "core/dom/ContextLifecycleObserver.h"
+#include "mojo/public/cpp/system/handle.h"
+
+namespace blink {
+
+class ExecutionContext;
+class MojoHandleSignals;
+class MojoWatchCallback;
+
+class MojoWatcher final : public GarbageCollectedFinalized<MojoWatcher>,
+                          public ActiveScriptWrappable<MojoWatcher>,
+                          public ScriptWrappable,
+                          public ContextLifecycleObserver {
+  DEFINE_WRAPPERTYPEINFO();
+  USING_GARBAGE_COLLECTED_MIXIN(MojoWatcher);
+
+ public:
+  static MojoWatcher* create(mojo::Handle,
+                             const MojoHandleSignals&,
+                             MojoWatchCallback*,
+                             ExecutionContext*);
+  ~MojoWatcher();
+
+  MojoResult cancel();
+
+  DECLARE_TRACE();
+  DECLARE_TRACE_WRAPPERS();
+
+  // ActiveScriptWrappable
+  bool hasPendingActivity() const final;
+
+  // ContextLifecycleObserver
+  void contextDestroyed(ExecutionContext*) final;
+
+ private:
+  friend class V8MojoWatcher;
+
+  MojoWatcher(mojo::Handle, MojoWatchCallback*, ExecutionContext*);
+  static void onHandleReady(uintptr_t context,
+                            MojoResult,
+                            MojoHandleSignalsState,
+                            MojoWatchNotificationFlags);
+  void runReadyCallback(MojoResult);
+
+  mojo::Handle m_handle;
+  TraceWrapperMember<MojoWatchCallback> m_callback;
+  RefPtr<WebTaskRunner> m_taskRunner;
+};
+
+}  // namespace blink
+
+#endif  // MojoWatcher_h