Build crash_service_win64 with clang-cl when is_clang=true

chrome/tools/crash_service/BUILD.gn

Index: chrome/tools/crash_service/BUILD.gn
diff --git a/chrome/tools/crash_service/BUILD.gn b/chrome/tools/crash_service/BUILD.gn
index df763ff9427d86ee5b97678c90ff44a165f3d91d..d24cb07f3f1828da96c54a2d4426ec735334e526 100644
--- a/chrome/tools/crash_service/BUILD.gn
+++ b/chrome/tools/crash_service/BUILD.gn
@@ -24,7 +24,13 @@ executable("crash_service") {
 if (target_cpu == "x86" && current_cpu == "x86") {
   # Cross-compile a 64-bit version when compiling a 64-bit target.
   copy("crash_service_win64") {
-    crash_service_64_target = ":crash_service(//build/toolchain/win:x64)"
+    if (is_clang) {
+      maybe_clang = "clang_"
+    } else {
+      maybe_clang = ""
+    }
+    crash_service_64_target =
+        ":crash_service(//build/toolchain/win:${maybe_clang}x64)"

[Dirk Pranke, 2016/03/29 18:56:08]

lgtm. 

There's a related issue in that is_clang is a toolchain-scoped variable (i.e.,
the value may change per toolchain) and so if this target got pulled in via
multiple toolchains we might end up declaring it multiple times. 

However, oddly, it looks like this target is really only referenced via the
chromium_builder_perf and telemetry_chrome_test targets, which can't be right,
so I'll try to clean this stuff up in a different follow-on CL.

 
     sources = [
       # It would be nice if get_target_outputs would work on the executable,