Correctly whitelist the PDF plugin in the PDF extension.

chrome/browser/pdf/pdf_extension_util.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/pdf/pdf_extension_util.h"
 
 #include "base/strings/string_util.h"
 #include "chrome/common/chrome_content_client.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/grit/browser_resources.h"
 #include "ui/base/resource/resource_bundle.h"
 
 namespace pdf_extension_util {
 
 namespace {
 
 // Tags in the manifest to be replaced.
 const char kNameTag[] = "<NAME>";
 const char kIndexTag[] = "<INDEX>";
 
 // The index html pages to load for the material and non-material version of
 // the viewer.
 const char kRegularIndex[] = "index.html";
 const char kMaterialIndex[] = "index-material.html";
 
 }  // namespace
 
+// These should match the keys for the Chrome and Chromium PDF Viewer entries in
+// chrome/browser/resources/plugin_metadata/plugins_*.json.
+#if defined(GOOGLE_CHROME_BUILD)
+const char kPdfResourceIdentifier[] = "google-chrome-pdf";
+#else
+const char kPdfResourceIdentifier[] = "chromium-pdf";
+#endif
+
 std::string GetManifest() {
   std::string manifest_contents =
       ResourceBundle::GetSharedInstance().GetRawDataResource(
           IDR_PDF_MANIFEST).as_string();
   DCHECK(manifest_contents.find(kNameTag) != std::string::npos);
   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);
   return manifest_contents;
 }
 
 }  // namespace pdf_extension_util