Default components to static libraries in GN build

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index fe59bcdfdb7e38b9c966af078ff163af8271bae7..9125a94a40efd78adda6235339b52df89a023b92 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -1063,7 +1063,10 @@ if (is_chrome_branded) {
 }
 
 # In GYP this is part of test_support_common.
-source_set("test_support") {
+#
+# Use a static library here because many test binaries depend on this but don't
+# require many files from it. This makes linking more efficient.
+static_library("test_support") {
   testonly = true
 
   # Always include this via the main test support target.