Copy ASan runtime to buildroot on Windows as well as Mac

build/config/sanitizers/BUILD.gn

Index: build/config/sanitizers/BUILD.gn
diff --git a/build/config/sanitizers/BUILD.gn b/build/config/sanitizers/BUILD.gn
index 1330a1f8aa3f2d66191b8d3e638eabedfa2197a8..4c98dd3a0b929bcd071a3cb6e6ec14d337a6d0a4 100644
--- a/build/config/sanitizers/BUILD.gn
+++ b/build/config/sanitizers/BUILD.gn
@@ -66,7 +66,7 @@ group("deps_no_options") {
       public_deps += [ "//buildtools/third_party/libc++:libcxx_proxy" ]
       data += [ "$root_out_dir/libc++.so" ]
     }
-    if (is_mac) {
+    if (is_mac || is_win) {
       data_deps = [
         ":copy_asan_runtime",
       ]
@@ -76,10 +76,17 @@ group("deps_no_options") {
   }
 }
 
-if (is_mac && using_sanitizer) {
+if ((is_mac || is_win) && using_sanitizer) {

[Dirk Pranke, 2016/08/03 00:06:10]

This isn't quite right, because now bundle_data("asan_runtime_bundle_data") will
be defined as a target as well. That one should be mac-only.

However, I think bundle_data() is a no-op on windows so it might be relatively
harmless.

   copy("copy_asan_runtime") {
+    if (is_mac) {
+      clang_rt_dso_path = "darwin/libclang_rt.asan_osx_dynamic.dylib"
+    } else if (is_win && target_cpu == "x86") {
+      clang_rt_dso_path = "windows/clang_rt.asan_dynamic-i386.dll"
+    } else if (is_win && target_cpu == "x64") {
+      clang_rt_dso_path = "windows/clang_rt.asan_dynamic-x86_64.dll"

[Nico, 2016/08/02 22:00:49]

Is this enough? atm asan is enabled for not just target binaries I think, so
from what I can tell in 32-bit builds we still build some nacl binaries in
64-bit with asan. We probably shouldn't do that, but at the moment I think we
do.

[Reid Kleckner, 2016/08/02 22:13:16]

I only know it's enough to make base_unittests and sbox_integration_tests start
working. :) Like you say, I think we can tackle the nacl thing separately.

+    }
     sources = [
-      "$clang_base_path/lib/clang/$clang_version/lib/darwin/libclang_rt.asan_osx_dynamic.dylib",
+      "$clang_base_path/lib/clang/$clang_version/lib/$clang_rt_dso_path",
     ]
     outputs = [
       "$root_out_dir/{{source_file_part}}",