Partial revert of commit c6d8683 to fix a GN + Win/Clang build warning.

BUG=547906
TBR=thakis@chromium.org

Review URL: https://codereview.chromium.org/1420503012 .
diff --git a/BUILD.gn b/BUILD.gn
index a2ddbad..7302863 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -554,9 +554,11 @@
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [
-    ":fxge_warnings",
     ":pdfium_config",
     "//build/config/compiler:no_chromium_code",
+    # As of this writing, this needs to be last to suppress a -Wswitch warning.
+    # https://crbug.com/547906
+    ":fxge_warnings",
   ]
 
   if (pdf_use_skia) {