[//cc] Add FakeLayerContext and have FakeLayerTreeFrameSink use it

A step toward getting cc_unittests to pass with VizLayers enabled. In
particular, this change gets the TileManager unittests to pass. We will
of course fill in FakeLayerContext as tests show need.

Bug: 383270106
Change-Id: I1ddba6df9aa44159730799804df0281c700fa306
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6089707
Reviewed-by: Jonathan Ross <jonross@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1395443}

cc/BUILD.gn

@@ -524,6 +524,7 @@ cc_test_static_library("test_support") {
     "test/fake_frame_info.cc",
     "test/fake_frame_info.h",
     "test/fake_impl_task_runner_provider.h",
+    "test/fake_layer_context.h",
     "test/fake_layer_tree_frame_sink.cc",
     "test/fake_layer_tree_frame_sink.h",
     "test/fake_layer_tree_frame_sink_client.cc",

cc/test/fake_layer_context.h

@@ -0,0 +1,34 @@
+// Copyright 2024 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CC_TEST_FAKE_LAYER_CONTEXT_H_
+#define CC_TEST_FAKE_LAYER_CONTEXT_H_
+
+#include "cc/cc_export.h"
+#include "cc/trees/layer_context.h"
+
+namespace cc {
+
+class CC_EXPORT FakeLayerContext : public LayerContext {
+ public:
+  FakeLayerContext() = default;
+  ~FakeLayerContext() override = default;
+
+  void SetVisible(bool visible) override {}
+
+  void UpdateDisplayTreeFrom(
+      LayerTreeImpl& tree,
+      viz::ClientResourceProvider& resource_provider,
+      viz::RasterContextProvider& context_provider) override {}
+
+  void UpdateDisplayTile(
+      PictureLayerImpl& layer,
+      const Tile& tile,
+      viz::ClientResourceProvider& resource_provider,
+      viz::RasterContextProvider& context_provider) override {}
+};
+
+}  // namespace cc
+
+#endif  // CC_TEST_FAKE_LAYER_CONTEXT_H_

cc/test/fake_layer_tree_frame_sink.cc

@@ -10,6 +10,7 @@
 #include "base/functional/bind.h"
 #include "base/memory/scoped_refptr.h"
 #include "base/task/single_thread_task_runner.h"
+#include "cc/test/fake_layer_context.h"
 #include "cc/tiles/image_decode_cache_utils.h"
 #include "cc/trees/layer_tree_frame_sink_client.h"
 #include "cc/trees/raster_context_provider_wrapper.h"
@@ -95,6 +96,11 @@ void FakeLayerTreeFrameSink::SubmitCompositorFrame(viz::CompositorFrame frame,
 void FakeLayerTreeFrameSink::DidNotProduceFrame(const viz::BeginFrameAck& ack,
                                                 FrameSkippedReason reason) {}
 
+std::unique_ptr<LayerContext> FakeLayerTreeFrameSink::CreateLayerContext(
+    LayerTreeHostImpl& host_impl) {
+  return std::make_unique<FakeLayerContext>();
+}
+
 void FakeLayerTreeFrameSink::DidAllocateSharedBitmap(
     base::ReadOnlySharedMemoryRegion region,
     const viz::SharedBitmapId& id) {

cc/test/fake_layer_tree_frame_sink.h

@@ -100,6 +100,8 @@ class FakeLayerTreeFrameSink : public LayerTreeFrameSink {
                              bool hit_test_data_changed) override;
   void DidNotProduceFrame(const viz::BeginFrameAck& ack,
                           FrameSkippedReason reason) override;
+  std::unique_ptr<LayerContext> CreateLayerContext(
+      LayerTreeHostImpl& host_impl) override;
   void DidAllocateSharedBitmap(base::ReadOnlySharedMemoryRegion region,
                                const viz::SharedBitmapId& id) override;
   void DidDeleteSharedBitmap(const viz::SharedBitmapId& id) override;