predictors: Key the resource prefetcher by URL, not navigation.

chrome/browser/predictors/resource_prefetch_predictor.cc

Index: chrome/browser/predictors/resource_prefetch_predictor.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor.cc b/chrome/browser/predictors/resource_prefetch_predictor.cc
index e60edfe70d01bea2e64d020b3a5b8de7dd3488a5..16ca46b00fbf737261d329bc8cf50b15be8c17fb 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor.cc
@@ -562,7 +562,7 @@ void ResourcePrefetchPredictor::StartPrefetching(
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::Bind(&ResourcePrefetcherManager::MaybeAddPrefetch,
-                 prefetch_manager_, navigation_id, key_type, urls));
+                 prefetch_manager_, navigation_id, urls));
 }
 
 void ResourcePrefetchPredictor::StopPrefetching(