cc: Clear the invalidation history when moving between compositors.

cc/layers/picture_layer_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 "cc/layers/picture_layer.h"
 
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/picture_layer_impl.h"
 #include "cc/resources/resource_update_queue.h"
 #include "cc/test/fake_layer_tree_host.h"
+#include "cc/test/fake_picture_layer.h"
 #include "cc/test/fake_picture_layer_impl.h"
 #include "cc/test/fake_proxy.h"
 #include "cc/test/impl_side_painting_settings.h"
 #include "cc/trees/occlusion_tracker.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
 namespace {
 
@@ skipping 83 matching lines @@
       FakeLayerTreeHost::Create(&host_client, settings);
   host->SetRootLayer(layer);
 
   // Tile-grid is set according to its setting.
   gfx::Size size =
       layer->GetRecordingSourceForTesting()->GetTileGridSizeForTesting();
   EXPECT_EQ(size.width(), 123);
   EXPECT_EQ(size.height(), 123);
 }
 
+TEST(PictureLayerTest, NonMonotonicSourceFrameNumber) {

[enne (OOO), 2015/02/26 20:46:04]

How would this fail before the change?

[danakj, 2015/02/26 21:10:23]

It would DCHECK.

[danakj, 2015/02/26 21:17:25]

Added comment.

+  LayerTreeSettings settings;
+  settings.single_thread_proxy_scheduler = false;
+
+  FakeLayerTreeHostClient host_client1(FakeLayerTreeHostClient::DIRECT_3D);
+  FakeLayerTreeHostClient host_client2(FakeLayerTreeHostClient::DIRECT_3D);
+  scoped_ptr<SharedBitmapManager> shared_bitmap_manager(
+      new TestSharedBitmapManager());
+
+  MockContentLayerClient client;
+  scoped_refptr<FakePictureLayer> layer = FakePictureLayer::Create(&client);
+
+  scoped_ptr<LayerTreeHost> host1 = LayerTreeHost::CreateSingleThreaded(
+      &host_client1, &host_client1, shared_bitmap_manager.get(), nullptr,
+      settings, base::MessageLoopProxy::current(), nullptr);
+  host_client1.SetLayerTreeHost(host1.get());
+
+  scoped_ptr<LayerTreeHost> host2 = LayerTreeHost::CreateSingleThreaded(
+      &host_client2, &host_client2, shared_bitmap_manager.get(), nullptr,
+      settings, base::MessageLoopProxy::current(), nullptr);
+  host_client2.SetLayerTreeHost(host2.get());
+
+  // The PictureLayer is put in one LayerTreeHost.
+  host1->SetRootLayer(layer);
+  // Do a main frame, record the picture layers.
+  EXPECT_EQ(0u, layer->update_count());
+  layer->SetNeedsDisplay();
+  host1->Composite(base::TimeTicks::Now());
+  EXPECT_EQ(1u, layer->update_count());
+  EXPECT_EQ(1, host1->source_frame_number());
+
+  // The source frame number in |host1| is now higher than host2.
+  layer->SetNeedsDisplay();
+  host1->Composite(base::TimeTicks::Now());
+  EXPECT_EQ(2u, layer->update_count());
+  EXPECT_EQ(2, host1->source_frame_number());
+
+  // Then moved to another LayerTreeHost.
+  host1->SetRootLayer(nullptr);
+  host2->SetRootLayer(layer);
+
+  // Do a main frame, record the picture layers. The frame number has changed
+  // non-monotonically.
+  layer->SetNeedsDisplay();
+  host2->Composite(base::TimeTicks::Now());
+  EXPECT_EQ(3u, layer->update_count());
+  EXPECT_EQ(1, host2->source_frame_number());
+}
+
 }  // namespace
 }  // namespace cc