Change the canonical way to include the C bindings headers to <mojo/bindings/*.h>.

mojo/public/c/include/mojo/bindings/interface.h

 // 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 MOJO_PUBLIC_C_BINDINGS_INTERFACE_H_
-#define MOJO_PUBLIC_C_BINDINGS_INTERFACE_H_
+#ifndef MOJO_PUBLIC_C_INCLUDE_MOJO_BINDINGS_INTERFACE_H_
+#define MOJO_PUBLIC_C_INCLUDE_MOJO_BINDINGS_INTERFACE_H_
 
 #include <mojo/macros.h>
 #include <mojo/system/handle.h>
 #include <stdint.h>
 
 MOJO_BEGIN_EXTERN_C
 
 // |MojomInterfaceData| represents a handle to an interface; in particular, this
 // is the client side of the interface where messages are sent and responses are
 // received. When encoded, |handle| represents the index into an array of
 // handles. The encoded version of an invalid handle is '-1' of MojoHandle type.
 struct MojomInterfaceData {
   MojoHandle handle;
   uint32_t version;
 };
 MOJO_STATIC_ASSERT(sizeof(struct MojomInterfaceData) == 8,
                    "struct MojomInterfaceData must be 8 bytes.");
 
 MOJO_END_EXTERN_C
 
-#endif  // MOJO_PUBLIC_C_BINDINGS_INTERFACE_H_
+#endif  // MOJO_PUBLIC_C_INCLUDE_MOJO_BINDINGS_INTERFACE_H_