Double-check safe-browsing database validity on update failure.

chrome/browser/safe_browsing/safe_browsing_store.h

Index: chrome/browser/safe_browsing/safe_browsing_store.h
diff --git a/chrome/browser/safe_browsing/safe_browsing_store.h b/chrome/browser/safe_browsing/safe_browsing_store.h
index a5b67fb96fd3c02b5689826a22e67989a312e37d..5b1e83145b4466a8d1d899fd87f0eaf9644069b2 100644
--- a/chrome/browser/safe_browsing/safe_browsing_store.h
+++ b/chrome/browser/safe_browsing/safe_browsing_store.h
@@ -220,6 +220,15 @@ class SafeBrowsingStore {
   virtual void DeleteAddChunk(int32 chunk_id) = 0;
   virtual void DeleteSubChunk(int32 chunk_id) = 0;
 
+  // May be called during update to verify that the storage is valid.
+  // Return true if the store seems valid.  If corruption is detected,
+  // calls the corruption callback and return false.
+  // NOTE(shess): When storage was SQLite, there was no guarantee that
+  // a structurally sound database actually contained valid data,
+  // whereas SafeBrowsingStoreFile checksums the data.  For now, this
+  // distinction doesn't matter.
+  virtual bool CheckValidity() = 0;
+
   // Pass the collected chunks through SBPRocessSubs() and commit to
   // permanent storage.  The resulting add prefixes and hashes will be
   // stored in |add_prefixes_result| and |add_full_hashes_result|.