Replacing hard-coded clang version by a common variable.

base/BUILD.gn

 # Copyright (c) 2013 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.
 
 # HOW TO WRITE CONDITIONALS IN THIS FILE
 # ======================================
 #
 # In many other places, one would write a conditional that expresses all the
 # cases when a source file is used or unused, and then either add or subtract
 # it from the sources list in that case
@@ skipping 1223 matching lines @@
           "$root_out_dir/api-ms-win-crt-utility-l1-1-0.dll",
           "$root_out_dir/ucrtbase${vcrt_suffix}.dll",
         ]
       } else {
         data += [
           "$root_out_dir/msvcp120${vcrt_suffix}.dll",
           "$root_out_dir/msvcr120${vcrt_suffix}.dll",
         ]
       }
       if (is_asan) {
-        data += [ "//third_party/llvm-build/Release+Asserts/lib/clang/3.9.0/lib/windows/clang_rt.asan_dynamic-i386.dll" ]
+        data += [ "//third_party/llvm-build/Release+Asserts/lib/clang/$clang_version/lib/windows/clang_rt.asan_dynamic-i386.dll" ]
       }
     }
 
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
     libs = [
       "cfgmgr32.lib",
       "netapi32.lib",
       "powrprof.lib",
@@ skipping 1106 matching lines @@
 
   # GYP: //base.gyp:base_java_unittest_support
   android_library("base_java_unittest_support") {
     deps = [
       ":base_java",
     ]
     java_files =
         [ "test/android/java/src/org/chromium/base/ContentUriTestUtils.java" ]
   }
 }