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..e9d3ae893d718db7ffd8e0041c97a6802cf8c298 100644
--- a/ppapi/proxy/pdf_resource.cc
+++ b/ppapi/proxy/pdf_resource.cc
@@ -89,7 +89,7 @@ void PDFResource::SearchString(const unsigned short* input_string,
 
   std::vector<PP_PrivateFindResult> pp_results;
   while (match_start != USEARCH_DONE) {
-    size_t matched_length = usearch_getMatchedLength(searcher);
+    int32_t matched_length = usearch_getMatchedLength(searcher);
     PP_PrivateFindResult result;
     result.start_index = match_start;
     result.length = matched_length;
@@ -98,7 +98,7 @@ void PDFResource::SearchString(const unsigned short* input_string,
     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)));