[chromecast] Fixes to CastScreen display override

  * Original CL was missing a single and critical line.
  * This CL also adds unit tests to verify.

Bug: internal b/138446155
Bug: internal b/141369532
Test: manual and unit test
Change-Id: I99707882c716fc371aa28aa29700f85eecb26638
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1816534Reviewed-by: Alex Sakhartchouk <alexst@chromium.org>
Commit-Queue: Ryan Daum <rdaum@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698568}

chromecast/graphics/BUILD.gn

@@ -127,6 +127,7 @@ if (use_aura && !is_cast_audio_only) {
       "accessibility/partial_magnification_controller_unittest.cc",
       "cast_display_util_unittest.cc",
       "cast_focus_client_aura_test.cc",
+      "cast_screen_unittest.cc",
       "cast_touch_event_gate_test.cc",
       "cast_views_test.cc",
       "cast_window_manager_aura_test.cc",

chromecast/graphics/cast_screen.cc

@@ -54,11 +54,14 @@ void CastScreen::OverridePrimaryDisplaySettings(
 
   stashed_display_settings_ = primary_display;
 
-  LOG(INFO) << "Stashing primary display settings; device_scale_factor: "
+  LOG(INFO) << "Stashing primary display (" << primary_display.id()
+            << ") settings; device_scale_factor: "
             << stashed_display_settings_->device_scale_factor()
             << " rotation: " << stashed_display_settings_->RotationAsDegree()
             << " size (pixels): "
             << stashed_display_settings_->GetSizeInPixel().ToString();
+
+  OnDisplayChanged(primary_display.id(), scale_factor, rotation, bounds);
 }
 
 bool CastScreen::RestorePrimaryDisplaySettings() {

chromecast/graphics/cast_screen_unittest.cc

+// Copyright 2019 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 "chromecast/graphics/cast_screen.h"
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "ui/aura/test/aura_test_base.h"
+#include "ui/display/display_observer.h"
+
+using testing::_;
+using testing::AllOf;
+using testing::Property;
+
+namespace chromecast {
+namespace test {
+
+namespace {
+constexpr int64_t kMockDisplayId = 0xcafebabe;
+}
+
+using CastScreenTest = aura::test::AuraTestBase;
+
+class MockDisplayObserver : public display::DisplayObserver {
+ public:
+  MOCK_METHOD2(OnDisplayMetricsChanged,
+               void(const display::Display& display, uint32_t changed_metrics));
+};
+
+TEST_F(CastScreenTest, OverrideAndRestore) {
+  MockDisplayObserver mock_display_observer;
+  CastScreen screen;
+  // Set up initial screen.
+  screen.OnDisplayChanged(kMockDisplayId, 1.0,
+                          display::Display::Rotation::ROTATE_0,
+                          gfx::Rect(0, 0, 1920, 1080));
+
+  EXPECT_CALL(mock_display_observer,
+              OnDisplayMetricsChanged(
+                  AllOf(Property(&display::Display::id, kMockDisplayId),
+                        Property(&display::Display::device_scale_factor, 2.2),
+                        Property(&display::Display::rotation,
+                                 display::Display::Rotation::ROTATE_270)),
+                  _));
+  EXPECT_CALL(mock_display_observer,
+              OnDisplayMetricsChanged(
+                  AllOf(Property(&display::Display::id, kMockDisplayId),
+                        Property(&display::Display::device_scale_factor, 1.0),
+                        Property(&display::Display::rotation,
+                                 display::Display::Rotation::ROTATE_0)),
+                  _));
+  screen.AddObserver(&mock_display_observer);
+  screen.OverridePrimaryDisplaySettings(gfx::Rect(0, 0, 1000, 1000), 2.2,
+                                        display::Display::Rotation::ROTATE_270);
+  screen.RestorePrimaryDisplaySettings();
+}
+
+}  // namespace test
+}  // namespace chromecast