[fuchsia] Make symbols in the Dart VM visible, so they are available to the profiler.

runtime/third_party/double-conversion/src/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 static_library("libdouble_conversion") {
   configs += [ "../../..:dart_config" ]
+  if (is_fuchsia) {
+    configs -= [ "//build/config:symbol_visibility_hidden" ]
+  }
   sources = [
     "bignum-dtoa.cc",
     "bignum-dtoa.h",
     "bignum.cc",
     "bignum.h",
     "cached-powers.cc",
     "cached-powers.h",
     "diy-fp.cc",
     "diy-fp.h",
     "double-conversion.cc",
     "double-conversion.h",
     "fast-dtoa.cc",
     "fast-dtoa.h",
     "fixed-dtoa.cc",
     "fixed-dtoa.h",
     "ieee.h",
     "strtod.cc",
     "strtod.h",
     "utils.h",
   ]
   include_dirs = [ "." ]
 }