[NTPSnippets] Show all downloads on the NTP (3/3): Downloads provider.

components/ntp_snippets/BUILD.gn

Index: components/ntp_snippets/BUILD.gn
diff --git a/components/ntp_snippets/BUILD.gn b/components/ntp_snippets/BUILD.gn
index 570dd0d82d87121956f898fda1da8531ff353525..f932e1be25e5f35687b1101a8abcc9df835707d3 100644
--- a/components/ntp_snippets/BUILD.gn
+++ b/components/ntp_snippets/BUILD.gn
@@ -116,8 +116,6 @@ source_set("unit_tests") {
     "bookmarks/bookmark_last_visit_utils_unittest.cc",
     "category_factory_unittest.cc",
     "content_suggestions_service_unittest.cc",
-    "mock_content_suggestions_provider_observer.cc",
-    "mock_content_suggestions_provider_observer.h",
     "offline_pages/recent_tab_suggestions_provider_unittest.cc",
     "physical_web_pages/physical_web_page_suggestions_provider_unittest.cc",
     "remote/ntp_snippet_unittest.cc",
@@ -133,14 +131,13 @@ source_set("unit_tests") {
 
   deps = [
     ":ntp_snippets",
+    ":test_support",
     "//base",
     "//base/test:test_support",
     "//components/bookmarks/browser",
     "//components/bookmarks/test",
     "//components/image_fetcher",
     "//components/leveldb_proto:test_support",
-    "//components/offline_pages",
-    "//components/offline_pages:test_support",
     "//components/sessions",
     "//components/sessions:test_support",
     "//components/signin/core/browser:test_support",
@@ -155,3 +152,19 @@ source_set("unit_tests") {
     "//ui/gfx:test_support",
   ]
 }
+
+source_set("test_support") {
+  testonly = true
+  sources = [
+    "mock_content_suggestions_provider_observer.cc",
+    "mock_content_suggestions_provider_observer.h",
+    "offline_pages/offline_pages_test_utils.cc",
+    "offline_pages/offline_pages_test_utils.h",
+  ]
+
+  deps = [
+    "//components/offline_pages",
+    "//components/offline_pages:test_support",
+    "//testing/gmock",
+  ]
+}