[gn check] Split "//headless:*" into 7 targets

Bug: 1158989
Change-Id: Idcf7d67d07d1540fcfcca6cfc0a367b1aa2ad5b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3172041
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Reviewed-by: Erik Staab <estaab@chromium.org>
Cr-Commit-Position: refs/heads/main@{#925795}

diff --git a/.gn b/.gn
index e1de7a7..6882be0 100644
--- a/.gn
+++ b/.gn

@@ -68,7 +68,16 @@
   "//extensions:chrome_extensions_browsertests",  # 26 errors
   "//extensions:chrome_extensions_interactive_uitests",  # 2 errors
 
-  "//headless:*",  # 107 errors
+  "//headless:headless_browsertests",  # 47 errors
+  "//headless:headless_browsertests__exec",
+  "//headless:headless_example",  # 3 errors
+  "//headless:headless_non_renderer",  # 9 errors
+  "//headless:headless_renderer",  # 13 errors
+  "//headless:headless_shared_sources",  # 4 errors
+  "//headless:headless_shell_browser_lib",  # 10 errors
+  "//headless:headless_shell_lib",  # 10 errors
+  "//headless:headless_unittests",  # 6 errors
+  "//headless:headless_unittests__exec",
 
   "//third_party/libwebp:*",  # 7 errors, https://crbug.com/800762