[Mac/GN] When using debug_devtools=true, bundle the inspector resources using a symlink.

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index b34a802103d38e49aa8886dbc18c133e9d5eb3e3..21de936b96591de9fef6c5a2a2ede5c16e04b8f3 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -855,7 +855,10 @@ if (!is_android) {
             ".",
             "//chrome")
 
-    configs += [ "//build/config:precompiled_headers" ]
+    configs += [
+      "//build/config:precompiled_headers",
+      "//third_party/WebKit/public:debug_devtools",
+    ]
 
     data = [
       "data/",
@@ -1044,9 +1047,6 @@ if (!is_android) {
         ]
       }
     }
-    if (debug_devtools) {
-      defines += [ "DEBUG_DEVTOOLS=1" ]
-    }
     if (use_ash) {
       sources +=
           rebase_path(chrome_tests_gypi_values.chrome_browser_tests_ash_sources,