Delete blimp/helium and remove references to it from dependent targets

blimp/helium/mock_objects.cc

-// 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.
-
-#include "blimp/helium/mock_objects.h"
-
-namespace blimp {
-namespace helium {
-
-TestSyncableChangeset::TestSyncableChangeset() : value(this) {}
-
-TestSyncableChangeset::~TestSyncableChangeset() {}
-
-TestSyncableChangeset& TestSyncableChangeset::operator=(
-    const TestSyncableChangeset& other) {
-  value.Set(other.value());
-  return *this;
-}
-
-MockSyncable::MockSyncable() = default;
-
-MockSyncable::~MockSyncable() = default;
-
-std::unique_ptr<TestSyncableChangeset> MockSyncable::CreateChangeset(
-    Revision from) const {
-  return base::WrapUnique<TestSyncableChangeset>(CreateChangesetMock(from));
-}
-
-MockStreamPump::MockStreamPump() = default;
-
-MockStreamPump::~MockStreamPump() = default;
-
-}  // namespace helium
-}  // namespace blimp