Include the implemented header first in all projects.

The Google C++ style guide dictates that foo.cc and foo_unittest.cc
should include foo.h in the first place, so missing headers in foo.h
are detected with a compile error of the module implementing them and
not when another module uses them.

This CL sweeps across all the .cc file in platform2 enforcing this.

BUG=None
TEST=cbuildbot amd64-generic

Change-Id: I41835835caba13f54c3c844ecf552eb0e47efa9d
Reviewed-on: https://chromium-review.googlesource.com/228894
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/modem_manager_unittest.cc b/modem_manager_unittest.cc
index 82ea6b3..b578a83 100644
--- a/modem_manager_unittest.cc
+++ b/modem_manager_unittest.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "shill/modem_manager.h"
+
 #include <base/stl_util.h>
 #include <ModemManager/ModemManager.h>
 
@@ -15,7 +17,6 @@
 #include "shill/mock_modem_manager_proxy.h"
 #include "shill/mock_proxy_factory.h"
 #include "shill/modem.h"
-#include "shill/modem_manager.h"
 #include "shill/testing.h"
 
 using std::string;