Add detailed UMA metrics for v4_store, broken down by storeid.

components/safe_browsing_db/v4_store_unittest.cc

Index: components/safe_browsing_db/v4_store_unittest.cc
diff --git a/components/safe_browsing_db/v4_store_unittest.cc b/components/safe_browsing_db/v4_store_unittest.cc
index 28191dad4c78179bb345c843134ec17d18fa9e55..c3824c858675a78fd6716f8b3a2759787ab78a50 100644
--- a/components/safe_browsing_db/v4_store_unittest.cc
+++ b/components/safe_browsing_db/v4_store_unittest.cc
@@ -711,7 +711,8 @@ TEST_F(V4StoreTest, TestAdditionsWithRiceEncodingFailsWithInvalidInput) {
   HashPrefixMap additions_map;
   EXPECT_EQ(RICE_DECODING_FAILURE,
             V4Store(task_runner_, store_path_)
-                .UpdateHashPrefixMapFromAdditions(additions, &additions_map));
+                .UpdateHashPrefixMapFromAdditions("V4Metric", additions,
+                                                  &additions_map));
 }
 #endif
 
@@ -732,7 +733,8 @@ TEST_F(V4StoreTest, TestAdditionsWithRiceEncodingSucceeds) {
   HashPrefixMap additions_map;
   EXPECT_EQ(APPLY_UPDATE_SUCCESS,
             V4Store(task_runner_, store_path_)
-                .UpdateHashPrefixMapFromAdditions(additions, &additions_map));
+                .UpdateHashPrefixMapFromAdditions("V4Metric", additions,
+                                                  &additions_map));
   EXPECT_EQ(1u, additions_map.size());
   EXPECT_EQ(std::string("\x5\0\0\0\fL\x93\xADV\x7F\xF6o\xCEo1\x81", 16),
             additions_map[4]);