Windows: Switch UWP build to using winrt generated headers (flutter#24861)

* Switch build to using generated headers

* Update DEPS to pick up newer buildroot

* Only run hook on Windows

Author: clarkezone

DEPS

@@ -97,7 +97,7 @@ allowed_hosts = [
 ]
 
 deps = {
-  'src': 'https://github.com/flutter/buildroot.git' + '@' + 'd05290fdfb0b8d2aad3c60bf0b4a76f368616452',
+  'src': 'https://github.com/flutter/buildroot.git' + '@' + '33358ba597f875f6646522fd4ea86c1b31404d77',
 
    # Fuchsia compatibility
    #
@@ -658,5 +658,16 @@ hooks = [
       'python',
       'src/flutter/tools/run_third_party_dart.py',
     ]
+  },
+  {
+    # This must run whenever the cppwinrt dependency is updated
+    # to regenerate winrt headers
+    'name': 'Generate winrt headers',
+    'pattern': '.',
+    'condition': 'download_windows_deps',
+    'action': [
+      'python',
+      'src/build/win/generate_winrt_headers.py',
+    ]
   }
 ]

shell/platform/windows/BUILD.gn

@@ -21,6 +21,17 @@ config("relative_flutter_windows_headers") {
   include_dirs = [ "public" ]
 }
 
+config("cppwinrt_defs") {
+  # Use winrt headers generated by the cppwinrt tool rather than those shipped in the installed SDK.
+  # The Windows metadata used to generate the headers does come from the installed SDK, by generating them rather than using the shipped ones
+  # the latest cppwinrt compatibility fixes can be derived.  For example, clang support is broken in the winrt headers shipped in SDK 10.0.19041.0.
+  # By generating them in the flutter toolchain using the SDK 10.0.19041.0 metadata and the latest version of the cppwinrt tool, that SDK version can be supported.
+  #
+  # Generated with command bin\cppwinrt.exe -in sdk -out generated
+  # by src\build\win\generate_winrt_headers.py
+  include_dirs = [ "..\..\..\..\third_party\cppwinrt\generated" ]
+}
+
 # The headers are a separate source set since the client wrapper is allowed
 # to depend on the public headers, but none of the rest of the code.
 source_set("flutter_windows_headers") {
@@ -119,6 +130,11 @@ source_set("flutter_windows_source") {
     ]
   }
 
+  if (target_os == "winuwp") {
+    configs += [ ":cppwinrt_defs" ]
+    cflags = [ "/EHsc" ]
+  }
+
   configs += [
     "//flutter/shell/platform/common:desktop_library_implementation",
     "//third_party/angle:gl_prototypes",

shell/platform/windows/angle_surface_manager.cc

@@ -8,8 +8,8 @@
 #include <vector>
 
 #ifdef WINUWP
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.Composition.h>
 #include <windows.ui.core.h>
-#include <winrt/Windows.UI.Composition.h>
 #endif
 
 #if defined(WINUWP) && defined(USECOREWINDOW)

shell/platform/windows/flutter_window_winuwp.h

@@ -5,14 +5,14 @@
 #ifndef FLUTTER_SHELL_PLATFORM_WINDOWS_UWP_FLUTTER_WINDOW_H_
 #define FLUTTER_SHELL_PLATFORM_WINDOWS_UWP_FLUTTER_WINDOW_H_
 
-#include <winrt/Windows.Graphics.Display.h>
-#include <winrt/Windows.System.Profile.h>
-#include <winrt/Windows.UI.Input.h>
-#include <winrt/Windows.UI.ViewManagement.Core.h>
-
+#include <third_party/cppwinrt/generated/winrt/Windows.Foundation.Collections.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.Graphics.Display.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.System.Profile.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.Composition.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.Core.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.Input.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.ViewManagement.Core.h>
 #include <windows.ui.core.h>
-#include <winrt/Windows.UI.Composition.h>
-#include <winrt/Windows.UI.Core.h>
 
 #include "flutter/shell/platform/embedder/embedder.h"
 #include "flutter/shell/platform/windows/flutter_windows_view.h"

shell/platform/windows/task_runner_winuwp.h

@@ -7,7 +7,7 @@
 
 #include <windows.h>
 
-#include <winrt/Windows.UI.Core.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.Core.h>
 
 #include <chrono>
 #include <functional>

shell/platform/windows/window_binding_handler.h

@@ -15,7 +15,7 @@
 #include "flutter/shell/platform/windows/window_binding_handler_delegate.h"
 
 #ifdef WINUWP
-#include <winrt/Windows.UI.Composition.h>
+#include <third_party/cppwinrt/generated/winrt/Windows.UI.Composition.h>
 #endif
 
 namespace flutter {