[Offline Pages] Adds Rappor metrics measuring what domains are saved & viewed.

components/offline_pages/offline_page_model_unittest.cc

Index: components/offline_pages/offline_page_model_unittest.cc
diff --git a/components/offline_pages/offline_page_model_unittest.cc b/components/offline_pages/offline_page_model_unittest.cc
index fa1b6f6976da8c921a580f962e155d1418a3872c..23f6b633c58e3405f4f54bac3f8a4b652c405d54 100644
--- a/components/offline_pages/offline_page_model_unittest.cc
+++ b/components/offline_pages/offline_page_model_unittest.cc
@@ -13,6 +13,7 @@
 #include "base/feature_list.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
+#include "base/memory/weak_ptr.h"
 #include "base/optional.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
@@ -42,6 +43,10 @@ using CheckPagesExistOfflineResult =
 using MultipleOfflineIdResult =
     offline_pages::OfflinePageModel::MultipleOfflineIdResult;
 
+namespace rappor {
+class RapporService;
+}
+
 namespace offline_pages {
 
 namespace {
@@ -274,8 +279,10 @@ std::unique_ptr<OfflinePageMetadataStore> OfflinePageModelTest::BuildStore() {
 
 std::unique_ptr<OfflinePageModel> OfflinePageModelTest::BuildModel(
     std::unique_ptr<OfflinePageMetadataStore> store) {
-  return std::unique_ptr<OfflinePageModel>(new OfflinePageModel(
-      std::move(store), temp_dir_.path(), base::ThreadTaskRunnerHandle::Get()));
+  return std::unique_ptr<OfflinePageModel>(
+      new OfflinePageModel(std::move(store), temp_dir_.path(),
+                           base::WeakPtr<rappor::RapporService>(),
+                           base::ThreadTaskRunnerHandle::Get()));
 }
 
 void OfflinePageModelTest::ResetModel() {