[inspector] fix timestamp formatting with non C locales

src/inspector/string-16.cc

 // Copyright 2016 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.
 
 #include "src/inspector/string-16.h"
 
 #include <algorithm>
 #include <cctype>
 #include <cstdlib>
 #include <cstring>
+#include <iomanip>
 #include <limits>
 #include <locale>
+#include <sstream>
 #include <string>
 
 #include "src/base/platform/platform.h"
 #include "src/inspector/protocol-platform.h"
 
 namespace v8_inspector {
 
 namespace {
 
 bool isASCII(UChar c) { return !(c & ~0x7F); }
@@ skipping 351 matching lines @@
 // static
 String16 String16::fromInteger(size_t number) {
   const size_t kBufferSize = 50;
   char buffer[kBufferSize];
   v8::base::OS::SNPrintF(buffer, kBufferSize, "%zu", number);
   return String16(buffer);
 }
 
 // static
 String16 String16::fromDouble(double number) {
-  const size_t kBufferSize = 100;
-  char buffer[kBufferSize];
-  v8::base::OS::SNPrintF(buffer, kBufferSize, "%f", number);
-  return String16(buffer);
+  std::ostringstream s;
+  s.imbue(std::locale("C"));
+  s << std::fixed << std::setprecision(std::numeric_limits<double>::digits10)
+    << number;
+  return String16(s.str().c_str());
 }
 
 // static
-String16 String16::fromDoublePrecision3(double number) {
-  const size_t kBufferSize = 100;
-  char buffer[kBufferSize];
-  v8::base::OS::SNPrintF(buffer, kBufferSize, "%.3g", number);
-  return String16(buffer);
-}
-
-// static
-String16 String16::fromDoublePrecision6(double number) {
-  const size_t kBufferSize = 100;
-  char buffer[kBufferSize];
-  v8::base::OS::SNPrintF(buffer, kBufferSize, "%.6g", number);
-  return String16(buffer);
+String16 String16::fromDouble(double number, int precision) {
+  std::ostringstream s;
+  s.imbue(std::locale("C"));
+  s << std::fixed << std::setprecision(precision) << number;
+  return String16(s.str().c_str());
 }
 
 int String16::toInteger(bool* ok) const {
   return charactersToInteger(characters16(), length(), ok);
 }
 
 String16 String16::stripWhiteSpace() const {
   if (!length()) return String16();
 
   size_t start = 0;
@@ skipping 100 matching lines @@
     // There should be room left, since one UChar hasn't been
     // converted.
     DCHECK((buffer + 3) <= (buffer + bufferVector.size()));
     putUTF8Triple(buffer, *characters);
   }
 
   return std::string(bufferVector.data(), buffer - bufferVector.data());
 }
 
 }  // namespace v8_inspector