Add a full Blimp integration test.

blimp/engine/browser_tests/waitable_content_pump.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blimp/engine/browser_tests/waitable_content_pump.h"
+
+#include "content/public/browser/browser_thread.h"
+#include "content/public/test/test_utils.h"
+
+namespace blimp {
+
+WaitableContentPump::WaitableContentPump()
+    : event_(base::WaitableEvent::ResetPolicy::MANUAL,
+             base::WaitableEvent::InitialState::NOT_SIGNALED) {}
+
+WaitableContentPump::~WaitableContentPump() = default;
+
+void WaitableContentPump::Wait() {
+  WaitFor(event());

[Khushal, 2016/09/13 23:47:10]

just &event_ here.

[David Trainor- moved to gerrit, 2016/09/14 00:31:09]

Done.

+}
+
+void WaitableContentPump::WaitFor(base::WaitableEvent* event) {
+  while (!event->IsSignaled()) {
+    content::RunAllPendingInMessageLoop(content::BrowserThread::UI);
+    content::RunAllPendingInMessageLoop(content::BrowserThread::IO);
+    content::RunAllPendingInMessageLoop(content::BrowserThread::FILE);
+  }
+  event->Reset();
+}
+
+}  // namespace blimp