Apply pdfium_noshorten_config to fpdfsdk/

Convert remaining code to avoid unchecked shortening conversions.

-- rewrite a loop in GetPageIndexByAnnotDict()

Change-Id: I396a058525de0ff90e96a39e0cc28a937cc94484
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/91353
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/fpdfsdk/BUILD.gn b/fpdfsdk/BUILD.gn
index 228e7c8..fe1abaa 100644
--- a/fpdfsdk/BUILD.gn
+++ b/fpdfsdk/BUILD.gn
@@ -71,7 +71,10 @@
     "ipdfsdk_annothandler.h",
   ]
 
-  configs += [ "../:pdfium_strict_config" ]
+  configs += [
+    "../:pdfium_strict_config",
+    "../:pdfium_noshorten_config",
+  ]
   deps = [
     "../:pdfium_public_headers",
     "../constants",