Refactor CRX verification in preparation to support CRX₃ files.

extensions/browser/sandboxed_unpacker.h

Index: extensions/browser/sandboxed_unpacker.h
diff --git a/extensions/browser/sandboxed_unpacker.h b/extensions/browser/sandboxed_unpacker.h
index 5b081df194529f223418b11ef554625d78d37477..c8bb78b33045bd66fa2d3e9bcb8c780b9b2cb6fe 100644
--- a/extensions/browser/sandboxed_unpacker.h
+++ b/extensions/browser/sandboxed_unpacker.h
@@ -5,6 +5,7 @@
 #ifndef EXTENSIONS_BROWSER_SANDBOXED_UNPACKER_H_
 #define EXTENSIONS_BROWSER_SANDBOXED_UNPACKER_H_
 
+#include <memory>
 #include <string>
 
 #include "base/files/file_path.h"
@@ -174,6 +175,10 @@ class SandboxedUnpacker : public base::RefCountedThreadSafe<SandboxedUnpacker> {
     UNZIP_FAILED,
     DIRECTORY_MOVE_FAILED,
 
+    // SandboxedUnpacker::ValidateSignature()
+    CRX_FILE_IS_DELTA_UPDATE,
+    CRX_EXPECTED_HASH_INVALID,
+
     NUM_FAILURE_REASONS
   };