Revert of [Memory UMA] Return the extra_processes_dump map as part of the ResponseCallback

mojo/common/process_id.mojom

Index: mojo/common/process_id.mojom
diff --git a/mojo/common/process_id.mojom b/mojo/common/process_id.mojom
deleted file mode 100644
index d72fe6eb96f0940c95494d8c0f7b1777ddc56868..0000000000000000000000000000000000000000
--- a/mojo/common/process_id.mojom
+++ /dev/null
@@ -1,12 +0,0 @@
-// 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.
-
-module mojo.common.mojom;
-
-struct ProcessId {
-  // This is the storage for the pid, on windows the pid is a DWORD and the
-  // value can be DWORD_MAX which maps gracefully to uint32 while on linux
-  // the pid is a signed int with a max value of 2^22.
-  uint32 pid;
-};