Add more string_util functions to base namespace.

chrome/browser/pdf/pdf_extension_util.cc

Index: chrome/browser/pdf/pdf_extension_util.cc
diff --git a/chrome/browser/pdf/pdf_extension_util.cc b/chrome/browser/pdf/pdf_extension_util.cc
index 7446087740af9fda6b40f0a3aa29270c4f0980c2..1987a6851db45af9356f5311ec5f0dfd3e6119c0 100644
--- a/chrome/browser/pdf/pdf_extension_util.cc
+++ b/chrome/browser/pdf/pdf_extension_util.cc
@@ -38,13 +38,13 @@ std::string GetManifest() {
       ResourceBundle::GetSharedInstance().GetRawDataResource(
           IDR_PDF_MANIFEST).as_string();
   DCHECK(manifest_contents.find(kNameTag) != std::string::npos);
-  ReplaceFirstSubstringAfterOffset(
+  base::ReplaceFirstSubstringAfterOffset(
       &manifest_contents, 0, kNameTag, ChromeContentClient::kPDFPluginName);
 
   DCHECK(manifest_contents.find(kIndexTag) != std::string::npos);
   std::string index = switches::PdfMaterialUIEnabled() ?
       kMaterialIndex : kRegularIndex;
-  ReplaceSubstringsAfterOffset(&manifest_contents, 0, kIndexTag, index);
+  base::ReplaceSubstringsAfterOffset(&manifest_contents, 0, kIndexTag, index);
   return manifest_contents;
 }