Move ".crx"/".pem" constants and extension_filenames constants into extensions/common/constants.cc.

chrome/browser/extensions/convert_web_app.cc

Index: chrome/browser/extensions/convert_web_app.cc
diff --git a/chrome/browser/extensions/convert_web_app.cc b/chrome/browser/extensions/convert_web_app.cc
index 5f844aba93fe6c56cdd8cd5d67cb59b7d42a5836..2ed22f32cda97e3e6a0e34278ac15a686c993785 100644
--- a/chrome/browser/extensions/convert_web_app.cc
+++ b/chrome/browser/extensions/convert_web_app.cc
@@ -57,8 +57,7 @@ std::string GenerateKey(const GURL& manifest_url) {
   return key;
 }
 
-}
-
+}  // namespace
 
 // Generates a version for the converted app using the current date. This isn't
 // really needed, but it seems like useful information.
@@ -144,7 +143,8 @@ scoped_refptr<Extension> ConvertWebAppToExtension(
   }
 
   // Write the manifest.
-  base::FilePath manifest_path = temp_dir.path().Append(kManifestFilename);
+  base::FilePath manifest_path = temp_dir.path().Append(
+      filenames::kManifestFilename);
   JSONFileValueSerializer serializer(manifest_path);
   if (!serializer.Serialize(*root)) {
     LOG(ERROR) << "Could not serialize manifest.";