update_engine: Remove GPIO support.

We have not used GPIO since Jan 2013. This CL removes the GPIO handling code.
As a side effect, it also removes dependency on libudev.

BUG=chromium:221725
CQ-DEPEND=CL:199683
TEST=unittest
TEST=AU end2end test on real device from older version to a version that
has CL applied, then from that to another newer version (need not have
this CL applied).

Change-Id: I4352488ec360b44a44b137c40a3ae4ec35c6fe9d
Reviewed-on: https://chromium-review.googlesource.com/199626
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Nam Nguyen <namnguyen@chromium.org>
Tested-by: Nam Nguyen <namnguyen@chromium.org>
diff --git a/update_check_scheduler.h b/update_check_scheduler.h
index a2dc41a..ec9e1a6 100644
--- a/update_check_scheduler.h
+++ b/update_check_scheduler.h
@@ -38,7 +38,6 @@
  public:
   static const int kTimeoutInitialInterval;
   static const int kTimeoutPeriodicInterval;
-  static const int kTimeoutQuickInterval;
   static const int kTimeoutRegularFuzz;
   static const int kTimeoutMaxBackoffInterval;
 
@@ -49,10 +48,8 @@
   // Initiates the periodic update checks, if necessary.
   void Run();
 
-  // Sets the new update status. This is invoked by UpdateAttempter.  |notice|
-  // is used for passing supplemental information about recent update events,
-  // which may influence scheduling decisions.
-  void SetUpdateStatus(UpdateStatus status, UpdateNotice notice);
+  // Sets the new update status. This is invoked by UpdateAttempter.
+  void SetUpdateStatus(UpdateStatus status);
 
   void set_poll_interval(int interval) { poll_interval_ = interval; }
   int poll_interval() const { return poll_interval_; }
@@ -97,15 +94,12 @@
   static gboolean StaticCheck(void* scheduler);
 
   // Schedules the next update check by setting up a timeout source;
-  // |is_force_quick| will enforce a quick subsequent update check interval.
-  void ScheduleNextCheck(bool is_force_quick);
+  void ScheduleNextCheck();
 
   // Computes the timeout interval along with its random fuzz range for the next
   // update check by taking into account the last timeout interval as well as
-  // the last update status. A nonzero |forced_interval|, however, will override
-  // all other considerations.
-  void ComputeNextIntervalAndFuzz(const int forced_interval,
-                                  int* next_interval, int* next_fuzz);
+  // the last update status.
+  void ComputeNextIntervalAndFuzz(int* next_interval, int* next_fuzz);
 
   // The UpdateAttempter to use for update checks.
   UpdateAttempter* update_attempter_;
@@ -122,9 +116,6 @@
   // Server dictated poll interval in seconds, if positive.
   int poll_interval_;
 
-  // A flag indicating whether a test update cycle was already attempted.
-  bool is_test_update_attempted_;
-
   // The external state of the system outside the update_engine process.
   SystemState* system_state_;