Initial UKMPageLoadMetricsObserver

components/ukm/BUILD.gn

Index: components/ukm/BUILD.gn
diff --git a/components/ukm/BUILD.gn b/components/ukm/BUILD.gn
index 0dabe32ed8fbb992f1b496369a031270e82cde53..e0afdcd27d22de3ee2c325390b10bf7d65837f68 100644
--- a/components/ukm/BUILD.gn
+++ b/components/ukm/BUILD.gn
@@ -14,6 +14,8 @@ static_library("ukm") {
     "ukm_pref_names.h",
     "ukm_service.cc",
     "ukm_service.h",
+    "ukm_source.cc",
+    "ukm_source.h",
   ]
 
   deps = [
@@ -25,6 +27,23 @@ static_library("ukm") {
   ]
 }
 
+static_library("test_support") {
+  testonly = true
+  sources = [
+    "test_ukm_service.cc",
+    "test_ukm_service.h",
+  ]
+
+  public_deps = [
+    ":ukm",
+  ]
+  deps = [
+    "//base",
+    "//components/metrics:test_support",
+    "//components/prefs:test_support",
+  ]
+}
+
 source_set("unit_tests") {
   testonly = true
   sources = [
@@ -32,6 +51,7 @@ source_set("unit_tests") {
   ]
 
   deps = [
+    ":test_support",
     ":ukm",
     "//base",
     "//base/test:test_support",