[tracing] Use locale independent writer for FP values.

test/cctest/test-traced-value.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/tracing/traced-value.h"
 #include "test/cctest/cctest.h"
 
 using v8::tracing::TracedValue;
 
 TEST(FlatDictionary) {
   auto value = TracedValue::Create();
   value->SetInteger("int", 2014);
   value->SetDouble("double", 0.0);
   value->SetBoolean("bool", true);
   value->SetString("string", "string");
   std::string json = "PREFIX";
   value->AppendAsTraceFormat(&json);
   CHECK_EQ(
-      "PREFIX{\"int\":2014,\"double\":0.000000,\"bool\":true,\"string\":"
+      "PREFIX{\"int\":2014,\"double\":0,\"bool\":true,\"string\":"
       "\"string\"}",
       json);
 }
 
 TEST(NoDotPathExpansion) {
   auto value = TracedValue::Create();
   value->SetInteger("in.t", 2014);
-  value->SetDouble("doub.le", 0.0);
+  value->SetDouble("doub.le", -20.25);
   value->SetBoolean("bo.ol", true);
   value->SetString("str.ing", "str.ing");
   std::string json;
   value->AppendAsTraceFormat(&json);
   CHECK_EQ(
-      "{\"in.t\":2014,\"doub.le\":0.000000,\"bo.ol\":true,\"str.ing\":\"str."
+      "{\"in.t\":2014,\"doub.le\":-20.25,\"bo.ol\":true,\"str.ing\":\"str."
       "ing\"}",
       json);
 }
 
 TEST(Hierarchy) {
   auto value = TracedValue::Create();
   value->SetInteger("i0", 2014);
   value->BeginDictionary("dict1");
   value->SetInteger("i1", 2014);
   value->BeginDictionary("dict2");
   value->SetBoolean("b2", false);
   value->EndDictionary();
   value->SetString("s1", "foo");
   value->EndDictionary();
   value->SetDouble("d0", 0.0);
+  value->SetDouble("d1", 10.5);
   value->SetBoolean("b0", true);
   value->BeginArray("a1");
   value->AppendInteger(1);
   value->AppendBoolean(true);
   value->BeginDictionary();
   value->SetInteger("i2", 3);
   value->EndDictionary();
   value->EndArray();
   value->SetString("s0", "foo");
 
   value->BeginArray("arr1");
   value->BeginDictionary();
   value->EndDictionary();
   value->BeginArray();
   value->EndArray();
   value->BeginDictionary();
   value->EndDictionary();
   value->EndArray();
 
   std::string json;
   value->AppendAsTraceFormat(&json);
   CHECK_EQ(
       "{\"i0\":2014,\"dict1\":{\"i1\":2014,\"dict2\":{\"b2\":false},"
-      "\"s1\":\"foo\"},\"d0\":0.000000,\"b0\":true,\"a1\":[1,true,{\"i2\":3}],"
-      "\"s0\":\"foo\",\"arr1\":[{},[],{}]}",
+      "\"s1\":\"foo\"},\"d0\":0,\"d1\":10.5,\"b0\":true,\"a1\":[1,true,{\"i2\":"
+      "3}],\"s0\":\"foo\",\"arr1\":[{},[],{}]}",
       json);
 }
 
 TEST(LongStrings) {
   std::string long_string = "supercalifragilisticexpialidocious";
   std::string long_string2 = "0123456789012345678901234567890123456789";
   char long_string3[4096];
   for (size_t i = 0; i < sizeof(long_string3); ++i)
     long_string3[i] = static_cast<char>('a' + (i % 26));
   long_string3[sizeof(long_string3) - 1] = '\0';
@@ skipping 32 matching lines @@
   // as it fails to process # character on Windows.
   const char* expected =
       "{\"a\":\"abc\\\"\'\\\\\\\\x\\\"y\'z\\n\\t\\u0017\",\"b\":"
       "\"\\u0001\\u0002\\u0003\\u0004\\u0005\\u0006\\u0007\\u0008\\t\\n\\u000B"
       "\\u000C\\u000D\\u000E\\u000F\\u0010\\u0011\\u0012\\u0013\\u0014\\u0015\\"
       "u0016\\u0017\\u0018\\u0019\\u001A\\u001B\\u001C\\u001D\\u001E\\u001F "
       "!\\\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]^_`"
       "abcdefghijklmnopqrstuvwxyz{|}~\177\"}";
   CHECK_EQ(expected, json);
 }