Move UKM PageLoad SourceId generation to PageLoadTracker.

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc

Index: chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc
diff --git a/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc
index 9d5b4af1f9c5641b93fbc34996114d02a5e43916..ac083d02c24a86acfa58bc113245dd2372898bc8 100644
--- a/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc
+++ b/chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer_unittest.cc
@@ -109,13 +109,14 @@ class TestDataReductionProxyMetricsObserver
   ~TestDataReductionProxyMetricsObserver() override {}
 
   // page_load_metrics::PageLoadMetricsObserver implementation:
-  ObservePolicy OnCommit(
-      content::NavigationHandle* navigation_handle) override {
+  ObservePolicy OnCommit(content::NavigationHandle* navigation_handle,
+                         ukm::SourceId source_id) override {
     DataReductionProxyData* data =
         DataForNavigationHandle(web_contents_, navigation_handle);
     data->set_used_data_reduction_proxy(data_reduction_proxy_used_);
     data->set_lofi_requested(lofi_used_);
-    return DataReductionProxyMetricsObserver::OnCommit(navigation_handle);
+    return DataReductionProxyMetricsObserver::OnCommit(navigation_handle,
+                                                       source_id);
   }
 
   DataReductionProxyPingbackClient* GetPingbackClient() const override {