Enforce variations signature verification.

chrome/browser/metrics/variations/variations_seed_store.h

Index: chrome/browser/metrics/variations/variations_seed_store.h
===================================================================
--- chrome/browser/metrics/variations/variations_seed_store.h	(revision 255631)
+++ chrome/browser/metrics/variations/variations_seed_store.h	(working copy)
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
 #include "base/time/time.h"
 
 class PrefService;
@@ -45,7 +46,30 @@
   // Registers Local State prefs used by this class.
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
+ protected:
+  // Note: UMA histogram enum - don't re-order or remove entries.
+  enum VerifySignatureResult {
+    VARIATIONS_SEED_SIGNATURE_MISSING,
+    VARIATIONS_SEED_SIGNATURE_DECODE_FAILED,
+    VARIATIONS_SEED_SIGNATURE_INVALID_SIGNATURE,
+    VARIATIONS_SEED_SIGNATURE_INVALID_SEED,
+    VARIATIONS_SEED_SIGNATURE_VALID,
+    VARIATIONS_SEED_SIGNATURE_ENUM_SIZE,
+  };
+
+  // Verifies a variations seed (the serialized proto bytes) with the specified
+  // base-64 encoded signature that was received from the server and returns the
+  // result. The signature is assumed to be an "ECDSA with SHA-256" signature
+  // (see kECDSAWithSHA256AlgorithmID in the .cc file). Returns the result of
+  // signature verification or VARIATIONS_SEED_SIGNATURE_ENUM_SIZE if signature
+  // verification is not enabled.
+  virtual VariationsSeedStore::VerifySignatureResult VerifySeedSignature(
+      const std::string& seed_bytes,
+      const std::string& base64_seed_signature);
+
  private:
+  FRIEND_TEST_ALL_PREFIXES(VariationsSeedStoreTest, VerifySeedSignature);
+
   // Clears all prefs related to variations seed storage.
   void ClearPrefs();