Retry to add MockPresentationClient to use in layout tests.

content/shell/renderer/test_runner/mock_presentation_service.cc

+// Copyright 2015 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 "content/shell/renderer/test_runner/mock_presentation_service.h"
+
+#include "base/logging.h"
+
+namespace content {
+
+MockPresentationService::MockPresentationService()
+    : screen_availability_(false) {
+}
+
+MockPresentationService::~MockPresentationService() {
+  DCHECK(!screen_availability_ && !presentation_clients_.might_have_observers())

[Peter Beverloo, 2015/02/12 17:39:20]

Was this DCHECK hitting because of screen_availability_ or because of having
clients?

If it's the former, could we instead only keep a Reset() method in this class
for setting |screen_availability_| to |false|, and still maintain the DCHECK for
not having clients?

I don't see why MockPresentationClient would be around for longer than
MockPresentationService, generally same-origin frames shouldn't outlive the page
they belong to.

[whywhat, 2015/02/12 18:40:13]

Having clients. Some added logging showed that at least one client is destroyed
after the service (I guess the client that belongs to the main frame).
I'll just keep Reset.

+      << "Reset() is not called before destroying the mock service.";
+}
+
+void MockPresentationService::SetScreenAvailability(bool available) {
+  if (screen_availability_ == available)
+    return;
+  screen_availability_ = available;
+
+  FOR_EACH_OBSERVER(
+      MockPresentationClient,
+      presentation_clients_,
+      SetScreenAvailability(available));
+}
+
+void MockPresentationService::Reset() {
+  FOR_EACH_OBSERVER(MockPresentationClient, presentation_clients_, Reset());
+  presentation_clients_.Clear();
+  screen_availability_ = false;
+}
+
+void MockPresentationService::RegisterPresentationClientMock(
+    MockPresentationClient* client) {
+  DCHECK(client);
+  presentation_clients_.AddObserver(client);
+}
+
+void MockPresentationService::UnregisterPresentationClientMock(
+    MockPresentationClient* client) {
+  DCHECK(client);
+  presentation_clients_.RemoveObserver(client);
+}
+
+}  // namespace content