Add KVO compliant title property to CWVWebView.

ios/web_view/test/BUILD.gn

Index: ios/web_view/test/BUILD.gn
diff --git a/ios/web_view/test/BUILD.gn b/ios/web_view/test/BUILD.gn
index b4dbe8275096002be1e2e47dc671f97293e119b4..faa821584a598b362aa59c408759c963cc3fa4a1 100644
--- a/ios/web_view/test/BUILD.gn
+++ b/ios/web_view/test/BUILD.gn
@@ -16,8 +16,6 @@ group("all_tests") {
 test("ios_web_view_inttests") {
   testonly = true
   sources = [
-    "boolean_observer.h",
-    "boolean_observer.mm",
     "chrome_web_view_kvo_inttest.mm",
     "chrome_web_view_test.h",
     "chrome_web_view_test.mm",
@@ -30,6 +28,7 @@ test("ios_web_view_inttests") {
     "//base/test:run_all_unittests",
     "//ios/testing:ios_test_support",
     "//ios/web_view:web_view+link",
+    "//ios/web_view/test/observers",
     "//net",
     "//net:test_support",
     "//testing/gtest",