--- a/chrome/browser/predictors/loading_data_collector.h
+++ b/chrome/browser/predictors/loading_data_collector.h
@@ -22,6 +22,9 @@
 #include "url/gurl.h"
 #include "url/origin.h"
 
+// base::flat_set is O(n), limit to a reasonable history length
+#define MAX_PREDICTOR_SUBRESOURCE_URL_HISTORY 4096
+
 namespace content {
 class NavigationHandle;
 }  // namespace content
--- a/chrome/browser/predictors/loading_data_collector.cc
+++ b/chrome/browser/predictors/loading_data_collector.cc
@@ -125,8 +125,18 @@
           net::SimplifyUrlForRequest(resource_load_info.final_url);
       if (is_low_priority) {
         low_priority_subresource_urls.insert(final_url);
+        // Prevent history bloat on long running pathological Web sites
+	if (low_priority_subresource_urls.size() >
+              MAX_PREDICTOR_SUBRESOURCE_URL_HISTORY) {
+          low_priority_subresource_urls.erase(
+              low_priority_subresource_urls.begin());
+        }
       } else {
         subresource_urls.insert(final_url);
+        // Prevent history bloat on long running pathological Web sites
+	if (subresource_urls.size() > MAX_PREDICTOR_SUBRESOURCE_URL_HISTORY) {
+          subresource_urls.erase(subresource_urls.begin());
+        }
       }
       return;
   }
k