Remove usage of deprecated std::codecvt

It was causing issues building Dawn in Skia. The error message helpfully
suggests using WideCharToMultiByte instead.

Bug: dawn:706
Change-Id: I87dee1192123f49cc8e7243a29df446389454df4
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/44560
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>

src/common/BUILD.gn

@@ -198,7 +198,6 @@ if (is_win || is_linux || is_chromeos || is_mac || is_fuchsia || is_android) {
       "ityp_stack_vec.h",
       "ityp_vector.h",
       "vulkan_platform.h",
-      "windows_with_undefs.h",
       "xlib_with_undefs.h",
     ]
 
@@ -207,6 +206,14 @@ if (is_win || is_linux || is_chromeos || is_mac || is_fuchsia || is_android) {
       "${dawn_root}/src/dawn:dawn_headers",
       "${dawn_root}/src/dawn:dawncpp_headers",
     ]
+
+    if (is_win) {
+      sources += [
+        "WindowsUtils.cpp",
+        "WindowsUtils.h",
+        "windows_with_undefs.h",
+      ]
+    }
     if (dawn_enable_vulkan) {
       public_deps = [ "${dawn_root}/third_party/khronos:vulkan_headers" ]
     }

src/common/CMakeLists.txt

@@ -61,9 +61,17 @@ target_sources(dawn_common PRIVATE
     "ityp_stack_vec.h"
     "ityp_vector.h"
     "vulkan_platform.h"
-    "windows_with_undefs.h"
     "xlib_with_undefs.h"
 )
+
+if (WIN32)
+    target_sources(dawn_common PRIVATE
+        "WindowsUtils.cpp"
+        "WindowsUtils.h"
+        "windows_with_undefs.h"
+    )
+endif()
+
 target_link_libraries(dawn_common PRIVATE dawn_internal_config)
 
 # TODO Android Log support

src/common/WindowsUtils.cpp

@@ -0,0 +1,32 @@
+// Copyright 2021 The Dawn Authors
+//
+// 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 "common/WindowsUtils.h"
+
+#include "common/windows_with_undefs.h"
+
+#include <memory>
+
+std::string WCharToUTF8(const wchar_t* input) {
+    // The -1 argument asks WideCharToMultiByte to use the null terminator to know the size of
+    // input. It will return a size that includes the null terminator.
+    int requiredSize = WideCharToMultiByte(CP_UTF8, 0, input, -1, nullptr, 0, nullptr, nullptr);
+
+    // When we can use C++17 this can be changed to use string.data() instead.
+    std::unique_ptr<char[]> result = std::make_unique<char[]>(requiredSize);
+    WideCharToMultiByte(CP_UTF8, 0, input, -1, result.get(), requiredSize, nullptr, nullptr);
+
+    // This will allocate the returned std::string and then destroy result.
+    return std::string(result.get(), result.get() + (requiredSize - 1));
+}

src/common/WindowsUtils.h

@@ -0,0 +1,22 @@
+// Copyright 2021 The Dawn Authors
+//
+// 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.
+
+#ifndef COMMON_WINDOWSUTILS_H_
+#define COMMON_WINDOWSUTILS_H_
+
+#include <string>
+
+std::string WCharToUTF8(const wchar_t* input);
+
+#endif  // COMMON_WINDOWSUTILS_H_