[sql] Consider fresh databases suitable for memory-mapped I/O.

chrome/browser/predictors/predictor_database.cc

Index: chrome/browser/predictors/predictor_database.cc
diff --git a/chrome/browser/predictors/predictor_database.cc b/chrome/browser/predictors/predictor_database.cc
index f948c4bdfc81f163cd5c7f3fbbb99525d4528f11..1d8721a1ed9cdf21cad92badb453c182ab2efc79 100644
--- a/chrome/browser/predictors/predictor_database.cc
+++ b/chrome/browser/predictors/predictor_database.cc
@@ -70,6 +70,11 @@ PredictorDatabaseInternal::PredictorDatabaseInternal(Profile* profile)
       autocomplete_table_(new AutocompleteActionPredictorTable()),
       resource_prefetch_tables_(new ResourcePrefetchPredictorTables()) {
   db_->set_histogram_tag("Predictor");
+
+  // TODO(shess): The current mitigation for http://crbug.com/537742 stores
+  // state in the meta table, which this database does not use.
+  db_->set_mmap_disabled();
+
   ResourcePrefetchPredictorConfig config;
   is_resource_prefetch_predictor_enabled_ =
       IsSpeculativeResourcePrefetchingEnabled(profile, &config);