[date] Refactor TimezoneCache to be separate from the OS

src/base/platform/platform-solaris.cc

Index: src/base/platform/platform-solaris.cc
diff --git a/src/base/platform/platform-solaris.cc b/src/base/platform/platform-solaris.cc
index 6783c6ba8922977e225581f0ce8d633f5601736c..d5cc658d73aab1de12325c72692a8c13534e42ed 100644
--- a/src/base/platform/platform-solaris.cc
+++ b/src/base/platform/platform-solaris.cc
@@ -28,14 +28,21 @@
 #undef MAP_TYPE
 
 #include "src/base/macros.h"
+#include "src/base/platform/platform-posix.h"
 #include "src/base/platform/platform.h"
 
-
 namespace v8 {
 namespace base {
 
+class SolarisTimezoneCache : public PosixTimezoneCache {
+  const char* LocalTimezone(double time) override;
+
+  double LocalTimeOffset() override;
 
-const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
+  ~SolarisTimezoneCache() override {}
+};
+
+const char* SolarisTimezoneCache::LocalTimezone(double time) {
   if (std::isnan(time)) return "";
   time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
   struct tm tm;
@@ -44,12 +51,12 @@ const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
   return tzname[0];  // The location of the timezone string on Solaris.
 }
 
-
-double OS::LocalTimeOffset(TimezoneCache* cache) {
+double SolarisTimezoneCache::LocalTimeOffset() {
   tzset();
   return -static_cast<double>(timezone * msPerSecond);
 }
 
+TimezoneCache* OS::CreateTimezoneCache() { return new SolarisTimezoneCache(); }
 
 void* OS::Allocate(const size_t requested,
                    size_t* allocated,