Fix GN generation for WinASAN build

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 9125c037a938df0672c69e84e87f373f3248706e..0dea8dd7e3516e1b7c643edba4cc820f3b4c7748 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -13,13 +13,14 @@
 # unpredictably for the various build types, we prefer a slightly different
 # style. Instead, there are big per-platform blocks of inclusions and
 # exclusions. If a given file has an inclusion or exclusion rule that applies
-# for multiple conditions, perfer to duplicate it in both lists. This makes it
+# for multiple conditions, prefer to duplicate it in both lists. This makes it
 # a bit easier to see which files apply in which cases rather than having a
 # huge sequence of random-looking conditionals.
 
 import("//build/buildflag_header.gni")
 import("//build/config/allocator.gni")
 import("//build/config/chromecast_build.gni")
+import("//build/config/clang/clang.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/nacl/config.gni")
@@ -1265,7 +1266,11 @@ component("base") {
         ]
       }
       if (is_asan) {
-        data += [ "//third_party/llvm-build/Release+Asserts/lib/clang/$clang_version/lib/windows/clang_rt.asan_dynamic-i386.dll" ]
+        if (current_cpu == "x64") {
+          data += [ "$clang_base_path/lib/clang/$clang_version/lib/windows/clang_rt.asan_dynamic-x86_64.dll" ]
+        } else {
+          data += [ "$clang_base_path/lib/clang/$clang_version/lib/windows/clang_rt.asan_dynamic-i386.dll" ]
+        }
       }
     }