update_engine: fixed warnings from cpplint

Fixed all the cpplint warnings in update engine.

BUG=None
TEST=Unit tests still pass.

Change-Id: I285ae858eec8abe0b26ff203b99a42a200ceb71c
Reviewed-on: https://chromium-review.googlesource.com/204027
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/fake_p2p_manager.h b/fake_p2p_manager.h
index 50de8d6..cbc063e 100644
--- a/fake_p2p_manager.h
+++ b/fake_p2p_manager.h
@@ -5,13 +5,15 @@
 #ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_P2P_MANAGER_H_
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_P2P_MANAGER_H_
 
+#include <string>
+
 #include "update_engine/p2p_manager.h"
 
 namespace chromeos_update_engine {
 
 // A fake implementation of P2PManager.
 class FakeP2PManager : public P2PManager {
-public:
+ public:
   FakeP2PManager() :
     is_p2p_enabled_(false),
     ensure_p2p_running_result_(false),
@@ -102,7 +104,7 @@
     lookup_url_for_file_result_ = url;
   }
 
-private:
+ private:
   bool is_p2p_enabled_;
   bool ensure_p2p_running_result_;
   bool ensure_p2p_not_running_result_;