Use more StringPieces in the PDF plugin.

pdf/out_of_process_instance.h

Index: pdf/out_of_process_instance.h
diff --git a/pdf/out_of_process_instance.h b/pdf/out_of_process_instance.h
index 22e1974ba1d2d64e8ecc38255e5671ce922cabdc..aeaca7a5320c71dbacc60a4868a37803831c7019 100644
--- a/pdf/out_of_process_instance.h
+++ b/pdf/out_of_process_instance.h
@@ -200,9 +200,9 @@ class OutOfProcessInstance : public pp::Instance,
   // Process the preview page data information. |src_url| specifies the preview
   // page data location. The |src_url| is in the format:
   // chrome://print/id/page_number/print.pdf
-  // |dst_page_index| specifies the blank page index that needs to be replaced
+  // |dest_page_index| specifies the blank page index that needs to be replaced
   // with the new page data.
-  void ProcessPreviewPageInfo(const std::string& src_url, int dst_page_index);
+  void ProcessPreviewPageInfo(const std::string& src_url, int dest_page_index);
   // Load the next available preview page into the blank page.
   void LoadAvailablePreviewPage();