predictors: Add origin learning.

chrome/browser/predictors/resource_prefetch_common.h

Index: chrome/browser/predictors/resource_prefetch_common.h
diff --git a/chrome/browser/predictors/resource_prefetch_common.h b/chrome/browser/predictors/resource_prefetch_common.h
index af03bee85c32e047ff876ead007764b31a369ae9..112c721e6a174f2388b7decf3c4108bba337f60c 100644
--- a/chrome/browser/predictors/resource_prefetch_common.h
+++ b/chrome/browser/predictors/resource_prefetch_common.h
@@ -110,6 +110,8 @@ struct ResourcePrefetchPredictorConfig {
 
   // The maximum number of resources to store per entry.
   size_t max_resources_per_entry;
+  // The maximum number of origins to store per entry.
+  size_t max_origins_per_entry;
   // The number of consecutive misses after we stop tracking a resource URL.
   size_t max_consecutive_misses;
 
@@ -126,6 +128,8 @@ struct ResourcePrefetchPredictorConfig {
   size_t max_prefetches_inflight_per_host_per_navigation;
   // True iff the predictor could use a url-based database.
   bool is_url_learning_enabled;
+  // True iff the origin-based prediction is enabled.
+  bool is_origin_prediction_enabled;
 };
 
 }  // namespace predictors