Merge latest changes from http://www.netlib.org/fp/dtoa.c into dtoa.cc

base/strings/string_number_conversions_unittest.cc

 // Copyright (c) 2012 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 "base/strings/string_number_conversions.h"
 
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
@@ skipping 872 matching lines @@
       {"8.32116e+55", 0x4b8b2628393e02cdULL},
   };
 
   for (const auto& test : cases) {
     double output;
     EXPECT_TRUE(StringToDouble(test.input, &output));
     EXPECT_EQ(bit_cast<uint64_t>(output), test.expected);
   }
 }
 
+TEST(StringNumberConversionsTest, StringToDoubleHangBug588726) {

[Lei Zhang, 2016/09/23 19:32:16]

Just add it to StringNumberConversionsTest.StringToDouble above?

[kcwu, 2016/09/23 19:48:03]

Done.

+  double output;
+  EXPECT_TRUE(StringToDouble(
+      "-0.0010000000000000000000000000000000000000001e-256", &output));
+  EXPECT_DOUBLE_EQ(-1.0000000000000001e-259, output);
+}
+
 }  // namespace base