Enable size_t to int truncation warnings in PPAPI

ppapi/proxy/pdf_resource.cc

Index: ppapi/proxy/pdf_resource.cc
diff --git a/ppapi/proxy/pdf_resource.cc b/ppapi/proxy/pdf_resource.cc
index 7d20d91026fc88b68cc44dc841985788a65b3fc5..aa185229957fee62977df747b9122f3b2f3fac6d 100644
--- a/ppapi/proxy/pdf_resource.cc
+++ b/ppapi/proxy/pdf_resource.cc
@@ -92,13 +92,13 @@ void PDFResource::SearchString(const unsigned short* input_string,
     size_t matched_length = usearch_getMatchedLength(searcher);
     PP_PrivateFindResult result;
     result.start_index = match_start;
-    result.length = matched_length;
+    result.length = static_cast<uint32_t>(matched_length);
     pp_results.push_back(result);
     match_start = usearch_next(searcher, &status);
     DCHECK(status == U_ZERO_ERROR);
   }
 
-  *count = pp_results.size();
+  *count = static_cast<uint32_t>(pp_results.size());
   if (*count) {
     *results = reinterpret_cast<PP_PrivateFindResult*>(malloc(
         *count * sizeof(PP_PrivateFindResult)));