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/update_manager/boxed_value.cc b/update_manager/boxed_value.cc
index 2307f8d..0acc8cd 100644
--- a/update_manager/boxed_value.cc
+++ b/update_manager/boxed_value.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 "update_engine/update_manager/boxed_value.h"
+
 #include <stdint.h>
 
 #include <set>
@@ -10,7 +12,6 @@
 #include <base/strings/string_number_conversions.h>
 #include <base/time/time.h>
 
-#include "update_engine/update_manager/boxed_value.h"
 #include "update_engine/update_manager/shill_provider.h"
 #include "update_engine/update_manager/updater_provider.h"
 #include "update_engine/utils.h"