Support gzip-compressed seed data from the variations server.

components/variations/variations_seed_store.h

Index: components/variations/variations_seed_store.h
diff --git a/components/variations/variations_seed_store.h b/components/variations/variations_seed_store.h
index e705a29f02e23a86c0d25749c6acfb4ad39b6c77..cb167fe6fe1bb88580e3e77bd7744ebc20a20d18 100644
--- a/components/variations/variations_seed_store.h
+++ b/components/variations/variations_seed_store.h
@@ -34,7 +34,9 @@ class VariationsSeedStore {
 
   // Stores the given seed |data| (serialized protobuf) to local state, along
   // with a base64-encoded digital signature for seed and the date when it was
-  // fetched. If |is_delta_compressed| is true, treats |data| as being delta
+  // fetched. If |is_gzip_compressed| is true, treats |data| as being gzip
+  // compressed and decompresses it before any other processing.
+  // If |is_delta_compressed| is true, treats |data| as being delta
   // compressed and attempts to decode it first using the store's seed data.
   // The actual seed data will be base64 encoded for storage. If the string
   // is invalid, the existing prefs are untouched and false is returned.
@@ -46,6 +48,7 @@ class VariationsSeedStore {
                      const std::string& country_code,
                      const base::Time& date_fetched,
                      bool is_delta_compressed,
+                     bool is_gzip_compressed,
                      variations::VariationsSeed* parsed_seed);
 
   // Updates |kVariationsSeedDate| and logs when previous date was from a