Add llvm fuzzer for CPDF_PSEngine

testing/libfuzzer/BUILD.gn

Index: testing/libfuzzer/BUILD.gn
diff --git a/testing/libfuzzer/BUILD.gn b/testing/libfuzzer/BUILD.gn
index 1b7a7fb45640a1a00c9d0f02f0dd92bd0e0b9bd0..718a1db3c0bf4afb386fe972012460a58cafbddd 100644
--- a/testing/libfuzzer/BUILD.gn
+++ b/testing/libfuzzer/BUILD.gn
@@ -168,3 +168,18 @@ source_set("pdf_jpx_fuzzer") {
     ":libfuzzer_config",
   ]
 }
+
+source_set("pdf_psengine_fuzzer") {
+  testonly = true
+  sources = [
+    "pdf_psengine_fuzzer.cc",
+  ]
+  deps = [
+    "//third_party/pdfium:pdfium",
+  ]
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [
+    "//build/config/compiler:no_chromium_code",
+    ":libfuzzer_config",
+  ]
+}