Remove jumbo usage in GN files throughout PDFium

Bug: pdfium:1410
Change-Id: I5769c94e19255b2f4ee1a95b34398ef37a125fc0
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/61870
Commit-Queue: Daniel Hosseinian <dhoss@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
diff --git a/fpdfsdk/BUILD.gn b/fpdfsdk/BUILD.gn
index e8d5774..afdbcf0 100644
--- a/fpdfsdk/BUILD.gn
+++ b/fpdfsdk/BUILD.gn
@@ -2,11 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build/config/jumbo.gni")
 import("../pdfium.gni")
 import("../testing/test.gni")
 
-jumbo_source_set("fpdfsdk") {
+source_set("fpdfsdk") {
   sources = [
     "cpdfsdk_actionhandler.cpp",
     "cpdfsdk_actionhandler.h",