Reland "[skia][libFuzzer] Allow building targets from OSS-Fuzz on Windows"

This is a reland of b8e27a0d

Original change's description:
> [skia][libFuzzer] Allow building targets from OSS-Fuzz on Windows
> 
> Chrome ClusterFuzz has support for Windows while OSS-Fuzz does not.
> Enable low hanging fruit that can easily be built in a Chromium build.
> 
> Bug: 903632
> Change-Id: I9b6c9bf883271d33135a4fea31a05be3d13648df
> Reviewed-on: https://chromium-review.googlesource.com/c/1328225
> Reviewed-by: Mike Klein <mtklein@chromium.org>
> Commit-Queue: Jonathan Metzman <metzman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#606938}

Bug: 903632
Change-Id: I35d49d83e589e04cf11215f63bbe2c2f13fab01c
Reviewed-on: https://chromium-review.googlesource.com/c/1330326Reviewed-by: Jonathan Metzman <metzman@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Jonathan Metzman <metzman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607290}

skia/BUILD.gn

@@ -9,6 +9,7 @@ import("//build/config/sanitizers/sanitizers.gni")
 import("//gpu/vulkan/features.gni")
 import("//printing/buildflags/buildflags.gni")
 import("//testing/test.gni")
+import("//testing/libfuzzer/fuzzer_test.gni")
 import("//third_party/skia/gn/shared_sources.gni")
 import("//third_party/skia/third_party/skcms/skcms.gni")
 
@@ -862,3 +863,156 @@ if (!is_ios) {
     ]
   }
 }
+
+# Build Skia fuzzers from OSS-Fuzz on Windows since Windows is not supported by
+# OSS-Fuzz.
+if (is_win && use_libfuzzer) {
+  static_library("skia_fuzzer_lib") {
+    sources = [
+      "//third_party/skia/fuzz/Fuzz.cpp",
+      "//third_party/skia/fuzz/FuzzCommon.cpp",
+    ]
+    configs += [ ":skia_library_config" ]
+
+    # Use public_deps so each fuzzer_test doesn't need to explicitly depend on
+    # ":skia".
+    public_deps = [
+      ":skia",
+    ]
+  }
+
+  static_library("skia_encoder_fuzzer_lib") {
+    sources = [
+      "//third_party/skia/fuzz/FuzzEncoders.cpp",
+    ]
+    configs += [ ":skia_library_config" ]
+    deps = [
+      ":skia",
+    ]
+  }
+
+  # TODO(metzman): Enable the other fuzzers that cannot yet build in Chromium.
+  fuzzer_test("skia_region_deserialize_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzRegionDeserialize.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_image_filter_deserialize_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzImageFilterDeserialize.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_region_set_path_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzRegionSetPath.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_textblob_deserialize_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzTextBlobDeserialize.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_path_deserialize_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzPathDeserialize.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_image_decode_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzImage.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_png_encoder_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzPNGEncoder.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_encoder_fuzzer_lib",
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_jpeg_encoder_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzJPEGEncoder.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_encoder_fuzzer_lib",
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_webp_encoder_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzWEBPEncoder.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_encoder_fuzzer_lib",
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_skjson_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzJSON.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+
+  fuzzer_test("skia_image_decode_incremental_fuzzer") {
+    sources = [
+      "//third_party/skia/fuzz/oss_fuzz/FuzzIncrementalImage.cpp",
+    ]
+    additional_configs = [ ":skia_library_config" ]
+    defines = [ "IS_FUZZING_WITH_LIBFUZZER" ]
+    deps = [
+      ":skia_fuzzer_lib",
+    ]
+  }
+}