Revert of [date] Add ICU backend for timezone info behind a flag

src/i18n.h

Index: src/i18n.h
diff --git a/src/i18n.h b/src/i18n.h
index 5b5aca4d5f1d3a9ba372676150db9ba0871c2778..f1c160f6049607849ff4f432f7d949492f7e5e14 100644
--- a/src/i18n.h
+++ b/src/i18n.h
@@ -6,7 +6,6 @@
 #ifndef V8_I18N_H_
 #define V8_I18N_H_
 
-#include "src/base/timezone-cache.h"
 #include "src/objects.h"
 #include "unicode/uversion.h"
 
@@ -15,7 +14,6 @@
 class Collator;
 class DecimalFormat;
 class SimpleDateFormat;
-class TimeZone;
 }
 
 namespace v8 {
@@ -140,34 +138,6 @@
 MUST_USE_RESULT Object* ConvertCase(Handle<String> s, bool is_upper,
                                     Isolate* isolate);
 
-// ICUTimezoneCache calls out to ICU for TimezoneCache
-// functionality in a straightforward way.
-class ICUTimezoneCache : public base::TimezoneCache {
- public:
-  ICUTimezoneCache();
-
-  ~ICUTimezoneCache() override;
-
-  const char* LocalTimezone(double time_ms) override;
-
-  double DaylightSavingsOffset(double time_ms) override;
-
-  double LocalTimeOffset() override;
-
-  void Clear() override;
-
- private:
-  icu::TimeZone* GetTimeZone();
-
-  bool GetOffsets(double time_ms, int32_t* raw_offset, int32_t* dst_offset);
-
-  icu::TimeZone* timezone_;
-
-  static const int32_t kMaxTimezoneChars = 100;
-  char timezone_name_[kMaxTimezoneChars];
-  char dst_timezone_name_[kMaxTimezoneChars];
-};
-
 }  // namespace internal
 }  // namespace v8