compile a flutter tester with SUPPORT_FRACTIONAL_TRANSLATION and raster cache disabled (flutter/engine#33272)

engine/src/flutter/BUILD.gn

@@ -101,6 +101,7 @@ group("flutter") {
   if (build_engine_artifacts) {
     public_deps += [
       "//flutter/shell/testing",
+      "//flutter/shell/testing:testing_fractional_translation",
       "//flutter/tools/const_finder",
       "//flutter/tools/font-subset",
     ]

engine/src/flutter/build/archives/BUILD.gn

@@ -13,6 +13,7 @@ if (build_engine_artifacts) {
       "//flutter/impeller/tessellator:tessellator_shared",
       "//flutter/lib/snapshot:generate_snapshot_bin",
       "//flutter/shell/testing:testing",
+      "//flutter/shell/testing:testing_fractional_translation",
     ]
     prefix = "$full_target_platform_name/"
     if (flutter_runtime_mode != "debug") {

engine/src/flutter/shell/testing/BUILD.gn

@@ -36,3 +36,44 @@ executable("testing") {
     "//third_party/skia",
   ]
 }
+
+# A second tester binary with SUPPORT_FRACTIONAL_TRANSLATION enabled
+# and the raster cache disabled.
+executable("testing_fractional_translation") {
+  output_name = "flutter_tester_fractional_translation"
+
+  public_configs = [
+    "//flutter:config",
+    "//flutter:export_dynamic_symbols",
+  ]
+
+  sources = [ "tester_main.cc" ]
+
+  if (is_win) {
+    libs = [
+      "psapi.lib",
+      "user32.lib",
+      "FontSub.lib",
+      "shlwapi.lib",
+    ]
+  }
+
+  defines = [
+    "SUPPORT_FRACTIONAL_TRANSLATION=1",
+    "DISABLE_SOFTWARE_RASTER_CACHE=1",
+  ]
+
+  deps = [
+    "//flutter/assets",
+    "//flutter/common",
+    "//flutter/flow",
+    "//flutter/fml",
+    "//flutter/lib/snapshot",
+    "//flutter/shell/common",
+    "//flutter/shell/gpu:gpu_surface_software",
+    "//flutter/third_party/tonic",
+    "//third_party/dart/runtime:libdart_jit",
+    "//third_party/dart/runtime/bin:dart_io_api",
+    "//third_party/skia",
+  ]
+}

engine/src/flutter/shell/testing/tester_main.cc

@@ -62,6 +62,18 @@ class TesterExternalViewEmbedder : public ExternalViewEmbedder {
   SkCanvas canvas_;
 };
 
+class TesterGPUSurfaceSoftware : public GPUSurfaceSoftware {
+ public:
+  TesterGPUSurfaceSoftware(GPUSurfaceSoftwareDelegate* delegate,
+                           bool render_to_surface)
+      : GPUSurfaceSoftware(delegate, render_to_surface) {}
+
+#if DISABLE_SOFTWARE_RASTER_CACHE
+  // |Surface|
+  bool EnableRasterCache() const override { return false; }
+#endif  // DISABLE_SOFTWARE_RASTER_CACHE
+};
+
 class TesterPlatformView : public PlatformView,
                            public GPUSurfaceSoftwareDelegate {
  public:
@@ -70,7 +82,7 @@ class TesterPlatformView : public PlatformView,
 
   // |PlatformView|
   std::unique_ptr<Surface> CreateRenderingSurface() override {
-    auto surface = std::make_unique<GPUSurfaceSoftware>(
+    auto surface = std::make_unique<TesterGPUSurfaceSoftware>(
         this, true /* render to surface */);
     FML_DCHECK(surface->IsValid());
     return surface;

engine/src/flutter/testing/run_tests.py

@@ -267,7 +267,7 @@ def RunEngineBenchmarks(build_dir, filter):
 
 
 def RunDartTest(build_dir, test_packages, dart_file, verbose_dart_snapshot, multithreaded,
-                enable_observatory=False, expect_failure=False):
+                enable_observatory=False, expect_failure=False, alternative_tester=False):
   kernel_file_name = os.path.basename(dart_file) + '.dill'
   kernel_file_output = os.path.join(build_dir, 'gen', kernel_file_name)
   error_message = "%s doesn't exist. Please run the build that populates %s" % (
@@ -296,9 +296,12 @@ def RunDartTest(build_dir, test_packages, dart_file, verbose_dart_snapshot, mult
   else:
     threading = 'single-threaded'
 
-  print("Running test '%s' using 'flutter_tester' (%s)" % (kernel_file_name, threading))
+  tester_name = 'flutter_tester'
+  if alternative_tester:
+    tester_name = 'flutter_tester_fractional_translation'
+  print("Running test '%s' using '%s' (%s)" % (kernel_file_name, tester_name, threading))
   forbidden_output = [] if 'unopt' in build_dir or expect_failure else ['[ERROR']
-  RunEngineExecutable(build_dir, 'flutter_tester', None, command_args,
+  RunEngineExecutable(build_dir, tester_name, None, command_args,
                       forbidden_output=forbidden_output, expect_failure=expect_failure)
 
 
@@ -442,6 +445,8 @@ def RunDartTests(build_dir, filter, verbose_dart_snapshot):
         print("Testing dart file %s with observatory enabled" % dart_test_file)
         RunDartTest(build_dir, test_packages, dart_test_file, verbose_dart_snapshot, True, True)
         RunDartTest(build_dir, test_packages, dart_test_file, verbose_dart_snapshot, False, True)
+        # Smoke test with tester variant that has no raster cache and enabled fractional translation
+        RunDartTest(build_dir, test_packages, dart_test_file, verbose_dart_snapshot, False, True, True)
 
   for dart_test_file in dart_tests:
     if filter is not None and os.path.basename(dart_test_file) not in filter: