Accept time zones like GMT-8 in the legacy date parser

src/dateparser-inl.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_DATEPARSER_INL_H_
 #define V8_DATEPARSER_INL_H_
 
 #include "src/char-predicates-inl.h"
 #include "src/dateparser.h"
 #include "src/unicode-cache-inl.h"
@@ skipping 119 matching lines @@
         if (has_read_number) return false;
         // The first number has to be separated from garbage words by
         // whitespace or other separators.
         if (scanner.Peek().IsNumber()) return false;
       }
     } else if (token.IsAsciiSign() && (tz.IsUTC() || !time.IsEmpty())) {
       // Parse UTC offset (only after UTC or time).
       tz.SetSign(token.ascii_sign());
       // The following number may be empty.
       int n = 0;
+      int length = 0;
       if (scanner.Peek().IsNumber()) {
-        n = scanner.Next().number();
+        DateToken token = scanner.Next();
+        length = token.length();
+        n = token.number();
       }
       has_read_number = true;
 
       if (scanner.Peek().IsSymbol(':')) {
         tz.SetAbsoluteHour(n);
+        // TODO(littledan): Use minutes as part of timezone?
         tz.SetAbsoluteMinute(kNone);
-      } else {
+      } else if (length == 2 || length == 1) {
+        // Handle time zones like GMT-8
+        tz.SetAbsoluteHour(n);
+        tz.SetAbsoluteMinute(0);
+      } else if (length == 4 || length == 3) {
+        // Looks like the hhmm format
         tz.SetAbsoluteHour(n / 100);
         tz.SetAbsoluteMinute(n % 100);
+      } else {
+        // No need to accept time zones like GMT-12345
+        return false;
       }
     } else if ((token.IsAsciiSign() || token.IsSymbol(')')) &&
                has_read_number) {
       // Extra sign or ')' is illegal if a number has been read.
       return false;
     } else {
       // Ignore other characters and whitespace.
     }
   }
 
@@ skipping 165 matching lines @@
   if (tz->IsEmpty()) tz->Set(0);
   day->set_iso_date();
   return DateToken::EndOfInput();
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_DATEPARSER_INL_H_