Refactor PPB_Flash GetLocalTimeZoneOffset to the new PPAPI resource model

ppapi/shared_impl/time_conversion.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/shared_impl/time_conversion.h"
 
 namespace ppapi {
 
 namespace {
 
@@ skipping 28 matching lines @@
 }
 
 PP_TimeTicks EventTimeToPPTimeTicks(double event_time) {
   return event_time + GetTimeToTimeTicksDeltaInSeconds();
 }
 
 double PPTimeTicksToEventTime(PP_TimeTicks t) {
   return t - GetTimeToTimeTicksDeltaInSeconds();
 }
 
+double PPGetLocalTimeZoneOffset(const base::Time& time) {
+  // Explode it to local time and then unexplode it as if it were UTC. Also
+  // explode it to UTC and unexplode it (this avoids mismatching rounding or
+  // lack thereof). The time zone offset is their difference.
+  base::Time::Exploded exploded = { 0 };
+  base::Time::Exploded utc_exploded = { 0 };
+  time.LocalExplode(&exploded);
+  time.UTCExplode(&utc_exploded);
+  if (exploded.HasValidValues() && utc_exploded.HasValidValues()) {
+    base::Time adj_time = base::Time::FromUTCExploded(exploded);
+    base::Time cur = base::Time::FromUTCExploded(utc_exploded);
+    return (adj_time - cur).InSecondsF();
+  }
+  return 0.0;
+}
+
 }  // namespace ppapi