Include implicit_cast.h at all users of it.

util/mach/mach_message_test.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #include "util/mach/mach_message.h"
 
 #include <unistd.h>
 
 #include "base/basictypes.h"
 #include "base/mac/scoped_mach_port.h"
 #include "gtest/gtest.h"
 #include "test/mac/mach_errors.h"
 #include "util/mach/mach_extensions.h"
+#include "util/misc/implicit_cast.h"
 
 namespace crashpad {
 namespace test {
 namespace {
 
 TEST(MachMessage, MachMessageDeadlineFromTimeout) {
   MachMessageDeadline deadline_0 =
       MachMessageDeadlineFromTimeout(kMachMessageTimeoutNonblocking);
   EXPECT_EQ(kMachMessageDeadlineNonblocking, deadline_0);
 
@@ skipping 110 matching lines @@
                                false);
   ASSERT_EQ(MACH_MSG_SUCCESS, mr)
       << MachErrorMessage(mr, "MachMessageWithDeadline receive");
 
   EXPECT_EQ(getpid(), AuditPIDFromMachMessageTrailer(&receive.trailer));
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad