Add a full Blimp integration test.

blimp/engine/browser_tests/blimp_browser_test.cc

Index: blimp/engine/browser_tests/blimp_browser_test.cc
diff --git a/blimp/engine/browser_tests/blimp_browser_test.cc b/blimp/engine/browser_tests/blimp_browser_test.cc
index 4da8f88c2a510310f0295279641449dce6508f63..67f72181deaf33342fa632bbe014cc815822f857 100644
--- a/blimp/engine/browser_tests/blimp_browser_test.cc
+++ b/blimp/engine/browser_tests/blimp_browser_test.cc
@@ -34,9 +34,9 @@ const char kClientAuthTokenFilePath[] = "blimp/test/data/test_client_token";
 const char kClientAuthToken[] = "MyVoiceIsMyPassport";
 }  // namespace
 
-
 BlimpBrowserTest::BlimpBrowserTest()
-    : completion_event_(base::WaitableEvent::ResetPolicy::MANUAL,
+    : engine_port_(0),
+      completion_event_(base::WaitableEvent::ResetPolicy::MANUAL,
                         base::WaitableEvent::InitialState::NOT_SIGNALED) {
   CreateTestServer(base::FilePath(FILE_PATH_LITERAL(kTestDataFilePath)));
 }
@@ -51,6 +51,12 @@ void BlimpBrowserTest::RunUntilCompletion() {
   completion_event_.Reset();
 }
 
+void BlimpBrowserTest::AllowUIWaits() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  allow_ui_waits_ =
+      base::MakeUnique<base::ThreadRestrictions::ScopedAllowWait>();
+}
+
 void BlimpBrowserTest::SignalCompletion() {
   completion_event_.Signal();
 }
@@ -102,6 +108,7 @@ void BlimpBrowserTest::SetUpOnMainThread() {
 }
 
 void BlimpBrowserTest::TearDownOnMainThread() {
+  allow_ui_waits_.reset();
   base::MessageLoop::current()->QuitWhenIdle();
 }