Add FrameGenerator Unit Tests

services/ui/ws/frame_generator_unittest.cc

+// Copyright 2017 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 "services/ui/ws/frame_generator.h"
+
+#include "base/macros.h"
+#include "cc/output/compositor_frame_sink.h"
+#include "cc/scheduler/begin_frame_source.h"
+#include "cc/test/begin_frame_args_test.cc"
+#include "cc/test/fake_external_begin_frame_source.h"
+#include "services/ui/ws/frame_generator_delegate.h"
+#include "services/ui/ws/server_window.h"
+#include "services/ui/ws/server_window_delegate.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace ui {
+namespace ws {
+namespace test {
+
+class TestFrameGeneratorDelegate : public FrameGeneratorDelegate {
+ public:
+  TestFrameGeneratorDelegate() {}
+  ~TestFrameGeneratorDelegate() override {}
+
+  // FrameGeneratorDelegate implementation:
+  bool IsInHighContrastMode() override { return false; }
+};
+
+class TestServerWindowDelegate : public ServerWindowDelegate {
+ public:
+  TestServerWindowDelegate() {}
+  ~TestServerWindowDelegate() override {}
+
+  // ServerWindowDelegate implementation:
+  cc::mojom::DisplayCompositor* GetDisplayCompositor() override {
+    return nullptr;
+  }
+
+  ServerWindow* GetRootWindow(const ServerWindow* window) override {
+    return nullptr;
+  }
+};
+
+// FakeCompositorFrameSink observes a FakeExternalBeginFrameSource and receives
+// CompositorFrame from a FrameGenerator.
+class FakeCompositorFrameSink : public cc::CompositorFrameSink,
+                                public cc::BeginFrameObserver,
+                                public cc::ExternalBeginFrameSourceClient {
+ public:
+  FakeCompositorFrameSink()
+      : cc::CompositorFrameSink(nullptr, nullptr, nullptr, nullptr) {}
+
+  // cc::CompositorFrameSink implementation:
+  bool BindToClient(cc::CompositorFrameSinkClient* client) override {
+    if (!cc::CompositorFrameSink::BindToClient(client))
+      return false;
+
+    external_begin_frame_source_ =
+        base::MakeUnique<cc::ExternalBeginFrameSource>(this);
+    client_->SetBeginFrameSource(external_begin_frame_source_.get());
+    return true;
+  }
+
+  void DetachFromClient() override {
+    cc::CompositorFrameSink::DetachFromClient();
+  }
+
+  void SubmitCompositorFrame(cc::CompositorFrame frame) override {
+    ++number_frames_received_;
+    last_frame_ = std::move(frame);
+  }
+
+  // cc::BeginFrameObserver implementation.
+  void OnBeginFrame(const cc::BeginFrameArgs& args) override {
+    external_begin_frame_source_->OnBeginFrame(args);
+    last_begin_frame_args_ = args;
+  }
+
+  const cc::BeginFrameArgs& LastUsedBeginFrameArgs() const override {
+    return last_begin_frame_args_;
+  }
+
+  void OnBeginFrameSourcePausedChanged(bool paused) override {}
+
+  // cc::ExternalBeginFrameSourceClient implementation:
+  void OnNeedsBeginFrames(bool needs_begin_frames) override {
+    needs_begin_frames_ = needs_begin_frames;
+    UpdateNeedsBeginFramesInternal();
+  }
+
+  void OnDidFinishFrame(const cc::BeginFrameAck& ack) override {
+    external_begin_frame_source_->DidFinishFrame(this, ack);
+  }
+
+  void SetBeginFrameSource(cc::BeginFrameSource* source) {
+    if (begin_frame_source_ && observing_begin_frames_) {
+      begin_frame_source_->RemoveObserver(this);
+      observing_begin_frames_ = false;
+    }
+    begin_frame_source_ = source;
+    UpdateNeedsBeginFramesInternal();
+  }
+
+  const cc::CompositorFrame& last_frame() { return last_frame_; }
+
+  int number_frames_received() { return number_frames_received_; }
+
+ private:
+  void UpdateNeedsBeginFramesInternal() {
+    if (!begin_frame_source_)
+      return;
+
+    if (needs_begin_frames_ == observing_begin_frames_)
+      return;
+
+    observing_begin_frames_ = needs_begin_frames_;
+    if (needs_begin_frames_) {
+      begin_frame_source_->AddObserver(this);
+    } else {
+      begin_frame_source_->RemoveObserver(this);
+    }
+  }
+
+  int number_frames_received_ = 0;
+  std::unique_ptr<cc::ExternalBeginFrameSource> external_begin_frame_source_;
+  cc::BeginFrameSource* begin_frame_source_ = nullptr;
+  cc::BeginFrameArgs last_begin_frame_args_;
+  cc::CompositorFrame last_frame_;
+  bool observing_begin_frames_ = false;
+  bool needs_begin_frames_ = false;
+};
+
+class FrameGeneratorTest : public testing::Test {
+ public:
+  FrameGeneratorTest() {}
+  ~FrameGeneratorTest() override {}
+
+  // testing::Test overrides:
+  void SetUp() override {
+    testing::Test::SetUp();
+
+    std::unique_ptr<FakeCompositorFrameSink> compositor_frame_sink =
+        base::MakeUnique<FakeCompositorFrameSink>();
+    compositor_frame_sink_ = compositor_frame_sink.get();
+
+    constexpr float kRefreshRate = 0.f;
+    constexpr bool kTickAutomatically = false;
+    begin_frame_source_ = base::MakeUnique<cc::FakeExternalBeginFrameSource>(
+        kRefreshRate, kTickAutomatically);
+    compositor_frame_sink_->SetBeginFrameSource(begin_frame_source_.get());
+    delegate_ = base::MakeUnique<TestFrameGeneratorDelegate>();
+    server_window_delegate_ = base::MakeUnique<TestServerWindowDelegate>();
+    root_window_ = base::MakeUnique<ServerWindow>(server_window_delegate_.get(),
+                                                  WindowId());
+    root_window_->SetVisible(true);
+    frame_generator_ = base::MakeUnique<FrameGenerator>(
+        delegate_.get(), root_window_.get(), std::move(compositor_frame_sink));
+  };
+
+  int NumberOfFramesReceived() {
+    return compositor_frame_sink_->number_frames_received();
+  }
+
+  void IssueBeginFrame() {
+    begin_frame_source_->TestOnBeginFrame(cc::CreateBeginFrameArgsForTesting(
+        BEGINFRAME_FROM_HERE, 0, next_sequence_number_));
+    ++next_sequence_number_;
+  }
+
+  FrameGenerator* frame_generator() { return frame_generator_.get(); }
+
+  const cc::SurfaceId& id_last_frame() {
+    return compositor_frame_sink_->last_frame()
+        .metadata.referenced_surfaces.front();
+  }
+
+ private:
+  FakeCompositorFrameSink* compositor_frame_sink_ = nullptr;
+  std::unique_ptr<cc::FakeExternalBeginFrameSource> begin_frame_source_;
+  std::unique_ptr<TestFrameGeneratorDelegate> delegate_;
+  std::unique_ptr<TestServerWindowDelegate> server_window_delegate_;
+  std::unique_ptr<ServerWindow> root_window_;
+  std::unique_ptr<FrameGenerator> frame_generator_;
+  int next_sequence_number_ = 1;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameGeneratorTest);
+};
+
+TEST_F(FrameGeneratorTest, OnSurfaceCreated) {
+  DCHECK_EQ(0, NumberOfFramesReceived());
+
+  // FrameGenerator does not request BeginFrames upon creation.
+  IssueBeginFrame();
+  EXPECT_EQ(0, NumberOfFramesReceived());
+
+  const cc::SurfaceId kArbitrarySurfaceId(
+      cc::FrameSinkId(1, 1),
+      cc::LocalSurfaceId(1, base::UnguessableToken::Create()));
+  const cc::SurfaceInfo kArbitrarySurfaceInfo(kArbitrarySurfaceId, 1.0f,
+                                              gfx::Size(100, 100));
+  frame_generator()->OnSurfaceCreated(kArbitrarySurfaceInfo);
+  // FrameGenerator gets the missed BeginFrame when AddObserver() is called.
+  EXPECT_EQ(0, NumberOfFramesReceived());

[brianderson, 2017/03/16 20:46:07]

@staraz mentioned this is 1 when MISSED frames are processed.

On it's own, this is okay.

+
+  IssueBeginFrame();
+  EXPECT_EQ(1, NumberOfFramesReceived());

[brianderson, 2017/03/16 20:46:07]

@staraz mentioned this is 2 when MISSED frames are processed.

This is the unexpected part. It seems like it would be better to not submit a
frame if there isn't anything new, rather than ignore MISSED frames.

Is that difficult to do? It would save an average of 8ms to get the frame up. I
also worry about what happens if you get two NORMAL BeginFrames.

[Alex Z., 2017/03/16 20:52:16]

We got 2 here because in FrameGenerator::SetNeedsBeginFrame(), 
observing_begin_frames_ is updated after AddObserver(). AddObserver() 
calls OnBeginFrame(MISSED args) calls SetNeedsBeginFrames(false) but 
both the argument and observing_begin_frames_ are false at this point 
so it early returns at the first if statement.

If we update observing_begin_frames_ before calling 
AddObserver()/RemoveObserver(), FrameGenerator only submit one 
CompositorFrame for the first (MISSED) args.

[Fady Samuel, 2017/03/16 21:06:35]

Ohh, yea, that's a bug. I think you're right. We should move the
observing_begin_frames_ BEFORE AddObserver...

[Alex Z., 2017/03/17 13:50:43]

Done.

+
+  // Verify that the CompositorFrame refers to the window manager's surface via
+  // referenced_surfaces.
+  cc::SurfaceId id = id_last_frame();
+  EXPECT_EQ(kArbitrarySurfaceId, id);
+
+  // FrameGenerator stops requesting BeginFrames after submitting a
+  // CompositorFrame.
+  IssueBeginFrame();
+  EXPECT_EQ(1, NumberOfFramesReceived());
+}
+
+TEST_F(FrameGeneratorTest, SetDeviceScaleFactor) {
+  DCHECK_EQ(0, NumberOfFramesReceived());
+  const cc::SurfaceId kArbitrarySurfaceId(
+      cc::FrameSinkId(1, 1),
+      cc::LocalSurfaceId(1, base::UnguessableToken::Create()));
+  const cc::SurfaceInfo kArbitrarySurfaceInfo(kArbitrarySurfaceId, 1.0f,
+                                              gfx::Size(100, 100));
+  constexpr float kDefaultScaleFactor = 1.0f;
+  constexpr float kArbitraryScaleFactor = 0.5f;
+
+  // A valid SurfaceInfo is required before setting device scale factor.
+  frame_generator()->OnSurfaceCreated(kArbitrarySurfaceInfo);
+  IssueBeginFrame();
+  DCHECK_EQ(1, NumberOfFramesReceived());
+
+  IssueBeginFrame();
+  DCHECK_EQ(1, NumberOfFramesReceived());
+
+  // FrameGenerator does not request BeginFrames if its device scale factor
+  // remains unchanged.
+  frame_generator()->SetDeviceScaleFactor(kDefaultScaleFactor);
+  IssueBeginFrame();
+  EXPECT_EQ(1, NumberOfFramesReceived());
+
+  frame_generator()->SetDeviceScaleFactor(kArbitraryScaleFactor);
+  IssueBeginFrame();
+  EXPECT_EQ(2, NumberOfFramesReceived());
+}
+
+}  // namespace test
+}  // namespace ws
+}  // namespace ui