apmanager: Rename "chromeos" -> "brillo" in include paths and namespaces

libchromeos is transitioning to libbrillo and chromeos namespaces
and include directory is changing to brillo.

Bug: 24872993
TEST=built for aosp and brillo, all unit tests pass on dragonboard
Change-Id: I4c6efbc5bbf80d251e5d91bc3db49f02bc0e4732
diff --git a/dhcp_server_unittest.cc b/dhcp_server_unittest.cc
index 5829d8a..d4cd2c5 100644
--- a/dhcp_server_unittest.cc
+++ b/dhcp_server_unittest.cc
@@ -22,7 +22,7 @@
 
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>
-#include <chromeos/process_mock.h>
+#include <brillo/process_mock.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <shill/net/mock_rtnl_handler.h>
@@ -30,7 +30,7 @@
 #include "apmanager/mock_file_writer.h"
 #include "apmanager/mock_process_factory.h"
 
-using chromeos::ProcessMock;
+using brillo::ProcessMock;
 using ::testing::_;
 using ::testing::Mock;
 using ::testing::Return;
@@ -86,7 +86,7 @@
   }
 
   void StartDummyProcess() {
-    dhcp_server_->dnsmasq_process_.reset(new chromeos::ProcessImpl);
+    dhcp_server_->dnsmasq_process_.reset(new brillo::ProcessImpl);
     dhcp_server_->dnsmasq_process_->AddArg(kBinSleep);
     dhcp_server_->dnsmasq_process_->AddArg("12345");
     CHECK(dhcp_server_->dnsmasq_process_->Start());