Reland PerformanceOverlayLayer golden test (flutter/engine#8140)

This reverts commit c416fe99ee0ddb464ca85c0b336d679ea626a03c.

Now we shouldn't break the engine build as https://chromium-review.googlesource.com/c/chromium/tools/build/+/1480746 is landed. The golden test is disabled by default and we'll enable it later in our recipe and test it in presubmit tests.

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -88,6 +88,7 @@ FILE: ../../../flutter/flow/layers/opacity_layer.cc
 FILE: ../../../flutter/flow/layers/opacity_layer.h
 FILE: ../../../flutter/flow/layers/performance_overlay_layer.cc
 FILE: ../../../flutter/flow/layers/performance_overlay_layer.h
+FILE: ../../../flutter/flow/layers/performance_overlay_layer_unittests.cc
 FILE: ../../../flutter/flow/layers/physical_shape_layer.cc
 FILE: ../../../flutter/flow/layers/physical_shape_layer.h
 FILE: ../../../flutter/flow/layers/picture_layer.cc
@@ -733,9 +734,13 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ====================================================================================================
 
 ====================================================================================================
+LIBRARY: engine
 LIBRARY: txt
 ORIGIN: ../../../flutter/third_party/txt/LICENSE
 TYPE: LicenseType.apache
+FILE: ../../../flutter/flow/flow_run_all_unittests.cc
+FILE: ../../../flutter/flow/flow_test_utils.cc
+FILE: ../../../flutter/flow/flow_test_utils.h
 FILE: ../../../flutter/third_party/txt/benchmarks/paint_record_benchmarks.cc
 FILE: ../../../flutter/third_party/txt/benchmarks/paragraph_benchmarks.cc
 FILE: ../../../flutter/third_party/txt/benchmarks/paragraph_builder_benchmarks.cc

engine/src/flutter/flow/BUILD.gn

@@ -93,13 +93,18 @@ executable("flow_unittests") {
   testonly = true
 
   sources = [
+    "flow_run_all_unittests.cc",
+    "flow_test_utils.h",
+    "flow_test_utils.cc",
     "matrix_decomposition_unittests.cc",
     "raster_cache_unittests.cc",
+    "layers/performance_overlay_layer_unittests.cc",
   ]
 
   deps = [
     ":flow",
-    "$flutter_root/testing",
+    "$flutter_root/fml",
+    "//third_party/googletest:gtest",
     "//third_party/dart/runtime:libdart_jit",  # for tracing
     "//third_party/skia",
   ]

engine/src/flutter/flow/flow_run_all_unittests.cc

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2017 Google, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "flutter/fml/command_line.h"
+#include "flutter/fml/logging.h"
+#include "gtest/gtest.h"
+
+#include "flow_test_utils.h"
+
+int main(int argc, char** argv) {
+  testing::InitGoogleTest(&argc, argv);
+  fml::CommandLine cmd = fml::CommandLineFromArgcArgv(argc, argv);
+  flow::SetGoldenDir(
+      cmd.GetOptionValueWithDefault("golden-dir", "flutter/testing/resources"));
+  flow::SetFontFile(cmd.GetOptionValueWithDefault(
+      "font-file",
+      "flutter/third_party/txt/third_party/fonts/Roboto-Regular.ttf"));
+  return RUN_ALL_TESTS();
+}

engine/src/flutter/flow/flow_test_utils.cc

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2017 Google, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string>
+
+namespace flow {
+
+static std::string gGoldenDir;
+static std::string gFontFile;
+
+const std::string& GetGoldenDir() {
+  return gGoldenDir;
+}
+
+void SetGoldenDir(const std::string& dir) {
+  gGoldenDir = dir;
+}
+
+const std::string& GetFontFile() {
+  return gFontFile;
+}
+
+void SetFontFile(const std::string& file) {
+  gFontFile = file;
+}
+
+}  // namespace flow

engine/src/flutter/flow/flow_test_utils.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2017 Google, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string>
+
+namespace flow {
+
+const std::string& GetGoldenDir();
+
+void SetGoldenDir(const std::string& dir);
+
+const std::string& GetFontFile();
+
+void SetFontFile(const std::string& dir);
+
+}  // namespace flow

engine/src/flutter/flow/layers/performance_overlay_layer.cc

@@ -15,8 +15,12 @@ namespace {
 void DrawStatisticsText(SkCanvas& canvas,
                         const std::string& string,
                         int x,
-                        int y) {
+                        int y,
+                        const std::string& font_path) {
   SkFont font;
+  if (font_path != "") {
+    font = SkFont(SkTypeface::MakeFromFile(font_path.c_str()));
+  }
   font.setSize(15);
   font.setLinearMetrics(false);
   SkPaint paint;
@@ -33,7 +37,8 @@ void VisualizeStopWatch(SkCanvas& canvas,
                         SkScalar height,
                         bool show_graph,
                         bool show_labels,
-                        const std::string& label_prefix) {
+                        const std::string& label_prefix,
+                        const std::string& font_path) {
   const int label_x = 8;    // distance from x
   const int label_y = -10;  // distance from y+height
 
@@ -51,14 +56,20 @@ void VisualizeStopWatch(SkCanvas& canvas,
     stream << label_prefix << "  "
            << "max " << max_ms_per_frame << " ms/frame, "
            << "avg " << average_ms_per_frame << " ms/frame";
-    DrawStatisticsText(canvas, stream.str(), x + label_x, y + height + label_y);
+    DrawStatisticsText(canvas, stream.str(), x + label_x, y + height + label_y,
+                       font_path);
   }
 }
 
 }  // namespace
 
-PerformanceOverlayLayer::PerformanceOverlayLayer(uint64_t options)
-    : options_(options) {}
+PerformanceOverlayLayer::PerformanceOverlayLayer(uint64_t options,
+                                                 const char* font_path)
+    : options_(options) {
+  if (font_path != nullptr) {
+    font_path_ = font_path;
+  }
+}
 
 void PerformanceOverlayLayer::Paint(PaintContext& context) const {
   const int padding = 8;
@@ -73,15 +84,15 @@ void PerformanceOverlayLayer::Paint(PaintContext& context) const {
   SkScalar height = paint_bounds().height() / 2;
   SkAutoCanvasRestore save(context.leaf_nodes_canvas, true);
 
-  VisualizeStopWatch(*context.leaf_nodes_canvas, context.frame_time, x, y,
-                     width, height - padding,
-                     options_ & kVisualizeRasterizerStatistics,
-                     options_ & kDisplayRasterizerStatistics, "GPU");
+  VisualizeStopWatch(
+      *context.leaf_nodes_canvas, context.frame_time, x, y, width,
+      height - padding, options_ & kVisualizeRasterizerStatistics,
+      options_ & kDisplayRasterizerStatistics, "GPU", font_path_);
 
   VisualizeStopWatch(*context.leaf_nodes_canvas, context.engine_time, x,
                      y + height, width, height - padding,
                      options_ & kVisualizeEngineStatistics,
-                     options_ & kDisplayEngineStatistics, "UI");
+                     options_ & kDisplayEngineStatistics, "UI", font_path_);
 }
 
 }  // namespace flow

engine/src/flutter/flow/layers/performance_overlay_layer.h

@@ -5,6 +5,8 @@
 #ifndef FLUTTER_FLOW_LAYERS_PERFORMANCE_OVERLAY_LAYER_H_
 #define FLUTTER_FLOW_LAYERS_PERFORMANCE_OVERLAY_LAYER_H_
 
+#include <string>
+
 #include "flutter/flow/layers/layer.h"
 #include "flutter/fml/macros.h"
 
@@ -17,12 +19,14 @@ const int kVisualizeEngineStatistics = 1 << 3;
 
 class PerformanceOverlayLayer : public Layer {
  public:
-  explicit PerformanceOverlayLayer(uint64_t options);
+  explicit PerformanceOverlayLayer(uint64_t options,
+                                   const char* font_path = nullptr);
 
   void Paint(PaintContext& context) const override;
 
  private:
   int options_;
+  std::string font_path_;
 
   FML_DISALLOW_COPY_AND_ASSIGN(PerformanceOverlayLayer);
 };

engine/src/flutter/flow/layers/performance_overlay_layer_unittests.cc

@@ -0,0 +1,96 @@
+// Copyright 2013 The Flutter 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 "flutter/flow/flow_test_utils.h"
+#include "flutter/flow/layers/performance_overlay_layer.h"
+#include "flutter/flow/raster_cache.h"
+
+#include "third_party/skia/include/core/SkSurface.h"
+#include "third_party/skia/include/utils/SkBase64.h"
+
+#include "gtest/gtest.h"
+
+// To get the size of kMockedTimes in compile time.
+template <class T, std::size_t N>
+constexpr int size(const T (&array)[N]) noexcept {
+  return N;
+}
+
+constexpr int kMockedTimes[] = {17, 1,  4,  24, 4,  25, 30, 4,  13, 34,
+                                14, 0,  18, 9,  32, 36, 26, 23, 5,  8,
+                                32, 18, 29, 16, 29, 18, 0,  36, 33, 10};
+
+// Relative to the flutter/src/engine/flutter directory
+const char* kGoldenFileName = "performance_overlay_gold.png";
+
+// Relative to the flutter/src/engine/flutter directory
+const char* kNewGoldenFileName = "performance_overlay_gold_new.png";
+
+TEST(PerformanceOverlayLayer, Gold) {
+  const std::string& golden_dir = flow::GetGoldenDir();
+  // This unit test should only be run on Linux (not even on Mac since it's a
+  // golden test). Hence we don't have to worry about the "/" vs. "\".
+  std::string golden_file_path = golden_dir + "/" + kGoldenFileName;
+  std::string new_golden_file_path = golden_dir + "/" + kNewGoldenFileName;
+
+  flow::Stopwatch mock_stopwatch;
+  for (int i = 0; i < size(kMockedTimes); ++i) {
+    mock_stopwatch.SetLapTime(
+        fml::TimeDelta::FromMilliseconds(kMockedTimes[i]));
+  }
+
+  const SkImageInfo image_info = SkImageInfo::MakeN32Premul(1000, 1000);
+  sk_sp<SkSurface> surface = SkSurface::MakeRaster(image_info);
+
+  ASSERT_TRUE(surface != nullptr);
+
+  flow::TextureRegistry unused_texture_registry;
+
+  flow::Layer::PaintContext paintContext = {
+      nullptr,        surface->getCanvas(),    nullptr, mock_stopwatch,
+      mock_stopwatch, unused_texture_registry, nullptr, false};
+
+  // Specify font file to ensure the same font across different operation
+  // systems.
+  flow::PerformanceOverlayLayer layer(flow::kDisplayRasterizerStatistics |
+                                          flow::kVisualizeRasterizerStatistics |
+                                          flow::kDisplayEngineStatistics |
+                                          flow::kVisualizeEngineStatistics,
+                                      flow::GetFontFile().c_str());
+  layer.set_paint_bounds(SkRect::MakeWH(1000, 400));
+  surface->getCanvas()->clear(SK_ColorTRANSPARENT);
+  layer.Paint(paintContext);
+
+  sk_sp<SkImage> snapshot = surface->makeImageSnapshot();
+  sk_sp<SkData> snapshot_data = snapshot->encodeToData();
+
+  sk_sp<SkData> golden_data =
+      SkData::MakeFromFileName(golden_file_path.c_str());
+  EXPECT_TRUE(golden_data != nullptr)
+      << "Golden file not found: " << golden_file_path << ".\n"
+      << "Please either set --golden-dir, or make sure that the unit test is "
+      << "run from the right directory (e.g., flutter/engine/src).";
+
+  const bool golden_data_matches = golden_data->equals(snapshot_data.get());
+  if (!golden_data_matches) {
+    SkFILEWStream wstream(new_golden_file_path.c_str());
+    wstream.write(snapshot_data->data(), snapshot_data->size());
+    wstream.flush();
+
+    size_t b64_size =
+        SkBase64::Encode(snapshot_data->data(), snapshot_data->size(), nullptr);
+    sk_sp<SkData> b64_data = SkData::MakeUninitialized(b64_size + 1);
+    char* b64_char = static_cast<char*>(b64_data->writable_data());
+    SkBase64::Encode(snapshot_data->data(), snapshot_data->size(), b64_char);
+    b64_char[b64_size] = 0;  // make it null terminated for printing
+
+    EXPECT_TRUE(golden_data_matches)
+        << "Golden file mismatch. Please check "
+        << "the difference between " << kGoldenFileName << " and "
+        << kNewGoldenFileName << ", and  replace the former "
+        << "with the latter if the difference looks good.\n\n"
+        << "See also the base64 encoded " << kNewGoldenFileName << ":\n"
+        << b64_char;
+  }
+}