Remove all blimp engine code

blimp/engine/app/blimp_engine_crash_keys.h

Index: blimp/engine/app/blimp_engine_crash_keys.h
diff --git a/blimp/engine/app/blimp_engine_crash_keys.h b/blimp/engine/app/blimp_engine_crash_keys.h
deleted file mode 100644
index ae3deebff117ab6630d583a77491ce2fada95dfd..0000000000000000000000000000000000000000
--- a/blimp/engine/app/blimp_engine_crash_keys.h
+++ /dev/null
@@ -1,20 +0,0 @@
-// 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 BLIMP_ENGINE_APP_BLIMP_ENGINE_CRASH_KEYS_H_
-#define BLIMP_ENGINE_APP_BLIMP_ENGINE_CRASH_KEYS_H_
-
-#include <stddef.h>
-
-namespace blimp {
-namespace engine {
-
-// Registers the crash keys needed for the Blimp engine. Returns the size of the
-// union of all keys.
-size_t RegisterEngineCrashKeys();
-
-}  // namespace engine
-}  // namespace blimp
-
-#endif  // BLIMP_ENGINE_APP_BLIMP_ENGINE_CRASH_KEYS_H_