Delete some unused code found by -Wunused-function

chrome/browser/ui/pdf/pdf_unsupported_feature.cc

Index: chrome/browser/ui/pdf/pdf_unsupported_feature.cc
diff --git a/chrome/browser/ui/pdf/pdf_unsupported_feature.cc b/chrome/browser/ui/pdf/pdf_unsupported_feature.cc
index b38fed0c6fab011030b0d3c9f181ead914816b8d..5ce9fd27f430184cea3c0bf745f66f8cf1acbf15 100644
--- a/chrome/browser/ui/pdf/pdf_unsupported_feature.cc
+++ b/chrome/browser/ui/pdf/pdf_unsupported_feature.cc
@@ -364,6 +364,7 @@ void PDFUnsupportedFeaturePromptDelegate::Cancel() {
                         UserMetricsAction("PDF_InstallReaderInfoBarCancel"));
 }
 
+#if defined(OS_WIN) && defined(ENABLE_PLUGIN_INSTALLATION)
 void GotPluginsCallback(int process_id,
                         int routing_id,
                         const std::vector<webkit::WebPluginInfo>& plugins) {
@@ -400,6 +401,7 @@ void GotPluginsCallback(int process_id,
   PDFTabHelper* pdf_tab_helper = PDFTabHelper::FromWebContents(web_contents);
   pdf_tab_helper->ShowOpenInReaderPrompt(prompt.Pass());
 }
+#endif  // defined(OS_WIN) && defined(ENABLE_PLUGIN_INSTALLATION)
 
 }  // namespace