Add Win OpenCL Build job.

Bug: skia:8081
Change-Id: Ibcb82389668bd9ea7395e498696417d5701761c0
Reviewed-on: https://skia-review.googlesource.com/140782
Commit-Queue: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 535eed2..3872bc4 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -2242,7 +2242,11 @@
         "tools/hello-opencl.cpp",
       ]
       include_dirs = [ "src/compute/common" ]
-      libs = [ "OpenCL" ]
+      if (is_linux) {
+        libs = [ "OpenCL" ]
+      } else if (is_win) {
+        libs = [ "OpenCL.lib" ]
+      }
     }
   }
 }