diff --git a/gn/BUILDCONFIG.gn b/gn/BUILDCONFIG.gn
index 188614c..acf4a54 100644
--- a/gn/BUILDCONFIG.gn
+++ b/gn/BUILDCONFIG.gn
@@ -33,6 +33,10 @@
   ios_min_target = ""
   ios_use_simulator =
       target_os == "ios" && (target_cpu == "x86" || target_cpu == "x64")
+
+  # Enable -H, which prints the include tree during compilation.
+  # For use by external tools for analyzing include files.
+  show_includes = false
 }
 declare_args() {
   is_debug = !is_official_build
diff --git a/gn/skia/BUILD.gn b/gn/skia/BUILD.gn
index bed7053..c712107 100644
--- a/gn/skia/BUILD.gn
+++ b/gn/skia/BUILD.gn
@@ -180,6 +180,21 @@
     ldflags += [ "-static-libstdc++" ]
   }
 
+  if (show_includes) {
+    assert(is_clang, "show_includes requires clang to build.")
+    if (is_win) {
+      cflags += [
+        "/clang:-H",
+        "/clang:-fshow-skipped-includes",
+      ]
+    } else {
+      cflags += [
+        "-H",
+        "-fshow-skipped-includes",
+      ]
+    }
+  }
+
   if (is_ios) {
     if (target_cpu == "arm") {
       _arch_flags = [