[inspector] Build inspector under v8_enable_inspector build flag.

include/v8-inspector-protocol.h

Index: include/v8-inspector-protocol.h
diff --git a/include/v8-inspector-protocol.h b/include/v8-inspector-protocol.h
new file mode 100644
index 0000000000000000000000000000000000000000..612a2ebc3911f59921ebd7c891fe5b0aba55fd19
--- /dev/null
+++ b/include/v8-inspector-protocol.h
@@ -0,0 +1,13 @@
+// Copyright 2016 the V8 project 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 V8_V8_INSPECTOR_PROTOCOL_H_
+#define V8_V8_INSPECTOR_PROTOCOL_H_
+
+#include "inspector/Debugger.h"  // NOLINT(build/include)
+#include "inspector/Runtime.h"   // NOLINT(build/include)
+#include "inspector/Schema.h"    // NOLINT(build/include)
+#include "v8-inspector.h"        // NOLINT(build/include)
+
+#endif  // V8_V8_INSPECTOR_PROTOCOL_H_