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 388532475c91952f7f5beda1a2527b648d08679e..2c628579c32d21c3f6a2cc94887219f782d3c8f1 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -78,7 +78,20 @@ if (is_desktop_linux) {
   }
 }
 
-source_set("browser") {
+# 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. However, on
+# x64 official builds the static library will be too large (> 32-bits) so use
+# source sets in that case.
+if (is_mac || (current_cpu == "x64" && is_official_build)) {
+  # TODO(brettw) bug 618797: Remove the mac condition. On Mac making this
+  # target a static_library causes a crash on startup and the browser_tests all
+  # fail. My guess is this is due to a required static initializer not being
+  # brought in.
+  chrome_browser_target_type = "source_set"
+} else {
+  chrome_browser_target_type = "static_library"
+}
+target(chrome_browser_target_type, "browser") {
   configs += [
     "//build/config/compiler:wexit_time_destructors",
     "//build/config:precompiled_headers",
@@ -1053,7 +1066,10 @@ 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.