[Mac/GN] Change two ldlfags to libs.

chrome/utility/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("../chrome_utility.gypi") ],
                           "scope",
                           [ "../chrome_utility.gypi" ])
 
 # Provides a way for the utility library to push ldflags to dependents.
 config("utility_ldflags") {
   if (is_mac && safe_browsing_mode == 1) {
-    ldflags = [ "/usr/lib/libbz2.dylib" ]
+    libs = [ "bz2" ]
   }
 }
 
 static_library("utility") {
   sources = rebase_path(gypi_values.chrome_utility_sources, ".", "..")
   defines = []
   configs += [ "//build/config:precompiled_headers" ]
   all_dependent_configs = [ ":utility_ldflags" ]
 
   public_deps = []
@@ skipping 82 matching lines @@
   if (safe_browsing_mode == 1) {
     sources +=
         rebase_path(gypi_values.chrome_utility_safe_browsing_sources, ".", "..")
     deps += [ "//third_party/zlib" ]
   }
 
   if (enable_pdf) {
     deps += [ "//pdf" ]
   }
 }