Fix undefined shift in DiyFpStrtod.

third_party/WebKit/Source/wtf/dtoa/strtod.cc

Index: third_party/WebKit/Source/wtf/dtoa/strtod.cc
diff --git a/third_party/WebKit/Source/wtf/dtoa/strtod.cc b/third_party/WebKit/Source/wtf/dtoa/strtod.cc
index d3b06199e758c67c03a8aad883344b342d43f0d9..998a0c4e912bcb9ab9bce844343c445685271378 100644
--- a/third_party/WebKit/Source/wtf/dtoa/strtod.cc
+++ b/third_party/WebKit/Source/wtf/dtoa/strtod.cc
@@ -264,7 +264,7 @@ namespace double_conversion {
         const int kDenominator = 1 << kDenominatorLog;
         // Move the remaining decimals into the exponent.
         exponent += remaining_decimals;
-        int error = (remaining_decimals == 0 ? 0 : kDenominator / 2);
+        int64_t error = (remaining_decimals == 0 ? 0 : kDenominator / 2);
 
         int old_e = input.e();
         input.Normalize();