headless: Implement client API generation

headless/public/headless_devtools_target.h

Index: headless/public/headless_devtools_target.h
diff --git a/headless/public/headless_devtools_target.h b/headless/public/headless_devtools_target.h
new file mode 100644
index 0000000000000000000000000000000000000000..941fe6f51e2ae640e9462d015f5c646005eebc5e
--- /dev/null
+++ b/headless/public/headless_devtools_target.h
@@ -0,0 +1,37 @@
+// 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.
+
+#ifndef HEADLESS_PUBLIC_HEADLESS_DEVTOOLS_TARGET_H_
+#define HEADLESS_PUBLIC_HEADLESS_DEVTOOLS_TARGET_H_
+
+#include "base/macros.h"
+#include "headless/public/headless_export.h"
+
+namespace headless {
+class HeadlessDevToolsClient;
+
+// A target which can be controlled and inspected using DevTools.
+class HEADLESS_EXPORT HeadlessDevToolsTarget {
+ public:
+  HeadlessDevToolsTarget() {}
+  virtual ~HeadlessDevToolsTarget() {}
+
+  // Attach or detach a client to this target. A client must be attached in
+  // order to send commands or receive notifications from the target.
+  //
+  // A single client may be attached to at most one target at a time. Note that
+  // currently also only one client may be attached to a single target at a
+  // time.
+  //
+  // |client| must outlive this target.
+  virtual void AttachClient(HeadlessDevToolsClient* client) = 0;
+  virtual void DetachClient(HeadlessDevToolsClient* client) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(HeadlessDevToolsTarget);
+};
+
+}  // namespace headless
+
+#endif  // HEADLESS_PUBLIC_HEADLESS_DEVTOOLS_TARGET_H_