Disable rendering when suspending on chrome os

ash/system/chromeos/power/power_event_observer_unittest.cc

 // Copyright 2013 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 "ash/system/chromeos/power/power_event_observer.h"
 
+#include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/power_manager_client.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_tree_host.h"
+#include "ui/compositor/compositor.h"
 
 namespace ash {
 
 class PowerEventObserverTest : public test::AshTestBase {
  public:
   PowerEventObserverTest() {}
   ~PowerEventObserverTest() override {}
 
   // test::AshTestBase::SetUp() overrides:
   void SetUp() override {
     test::AshTestBase::SetUp();
     observer_.reset(new PowerEventObserver());
   }
 
   void TearDown() override {
     observer_.reset();
     test::AshTestBase::TearDown();
   }
 
  protected:
+  void ExpectCompositorVisibility(bool expected) {

[Daniel Erat, 2015/02/11 14:11:43]

to get more-meaningful failure messages, how about changing this to
GetNumVisibleCompositors() and then comparing it against the total number of
compositors or 0 (depending on whether compositing should be active or frozen)
in the tests below?

[Chirantan Ekbote, 2015/02/18 02:47:13]

Done.

+    for (const auto& window : Shell::GetAllRootWindows()) {

[Daniel Erat, 2015/02/11 14:11:42]

nit: omit curly brackets

+      EXPECT_EQ(expected, window->GetHost()->compositor()->IsVisible());
+    }
+  }
+
   scoped_ptr<PowerEventObserver> observer_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PowerEventObserverTest);
 };
 
 TEST_F(PowerEventObserverTest, LockBeforeSuspend) {
   chromeos::PowerManagerClient* client =
       chromeos::DBusThreadManager::Get()->GetPowerManagerClient();
   ASSERT_EQ(0, client->GetNumPendingSuspendReadinessCallbacks());
@@ skipping 18 matching lines @@
   EXPECT_EQ(0, client->GetNumPendingSuspendReadinessCallbacks());
 
   // It also shouldn't request a callback if it isn't instructed to lock the
   // screen.
   observer_->SuspendDone(base::TimeDelta());
   SetShouldLockScreenBeforeSuspending(false);
   observer_->SuspendImminent();
   EXPECT_EQ(0, client->GetNumPendingSuspendReadinessCallbacks());
 }
 
+TEST_F(PowerEventObserverTest, SetInvisibleBeforeSuspend) {
+  // Tests that all the LayerTreeHosts are marked invisible before a suspend
+  // request when the screen is not supposed to be locked before a suspend.
+  ExpectCompositorVisibility(true);
+
+  observer_->SuspendImminent();
+  ExpectCompositorVisibility(false);
+  observer_->SuspendDone(base::TimeDelta());
+
+  // Tests that all the LayerTreeHosts are marked invisible _after_ the screen
+  // is locked for a suspend request.
+  SetCanLockScreen(true);
+  SetShouldLockScreenBeforeSuspending(true);
+
+  observer_->SuspendImminent();
+  ExpectCompositorVisibility(true);
+
+  observer_->ScreenIsLocked();
+  ExpectCompositorVisibility(false);
+
+  observer_->SuspendDone(base::TimeDelta());
+  ExpectCompositorVisibility(true);
+}
+
+TEST_F(PowerEventObserverTest, CanceledSuspend) {
+  // Tests that the LayerTreeHosts are not marked invisible if a suspend is
+  // canceled before the lock screen is ready.

[Daniel Erat, 2015/02/11 14:11:43]

nit: s/canceled/canceled or resumed/

[Chirantan Ekbote, 2015/02/18 02:47:13]

Done.

+  SetCanLockScreen(true);
+  SetShouldLockScreenBeforeSuspending(true);
+  observer_->SuspendImminent();
+  ExpectCompositorVisibility(true);
+
+  observer_->SuspendDone(base::TimeDelta());
+  observer_->ScreenIsLocked();
+  ExpectCompositorVisibility(true);
+}
+
 }  // namespace ash