Standalone GN build.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 026ffc58ace14b2ba987da50c4701cc034b5042a..1d66751b75fbeb481d959cb2f075efb9c5a966a4 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1696,7 +1696,7 @@ test("pdfium_embeddertests") {
     "//testing/gmock",
     "//testing/gtest",
   ]
-  include_dirs = []
+  include_dirs = [ "testing/gmock/include" ]
   if (pdf_enable_v8) {
     sources += [
       "fpdfsdk/javascript/public_methods_embeddertest.cpp",
@@ -1716,3 +1716,12 @@ test("pdfium_embeddertests") {
   }
   configs += [ ":pdfium_config" ]
 }
+
+if (pdf_is_standalone) {
+  source_set("samples") {
+    testonly = true
+    deps = [
+      "//samples",
+    ]
+  }
+}