update win build

engine/Build.bee.cs

                 "src/engine.cc",
                 "src/platform_base.h",
             },
-            OutputName = { c => $"libUIWidgets{(c.CodeGen == CodeGen.Debug ? "_d" : "")}" },
+            OutputName = { c => "libUIWidgets" },
         };
 
         // include these files for test only
             return new PrecompiledLibrary[]
             {
                 new StaticLibrary(flutterRoot+"/out/host_debug_unopt/obj/flutter/third_party/txt/txt_lib.lib"),
+                new StaticLibrary(flutterRoot+"/out/host_debug_unopt/obj/third_party/angle/angle_lib.lib"),
+                new StaticLibrary(flutterRoot+"/out/host_debug_unopt/obj/third_party/angle/libEGL_static.lib"),
+                new StaticLibrary(flutterRoot+"/out/host_debug_unopt/obj/third_party/angle/libGLESv2_static.lib"),
+                new SystemLibrary("dxguid.lib"),
             };
         });
 
             return new PrecompiledLibrary[]
             {
                 new StaticLibrary(flutterRoot+"/out/host_release/obj/flutter/third_party/txt/txt_lib.lib"),
+                new StaticLibrary(flutterRoot+"/out/host_release/obj/third_party/angle/angle_lib.lib"),
+                new StaticLibrary(flutterRoot+"/out/host_release/obj/third_party/angle/libEGL_static.lib"),
+                new StaticLibrary(flutterRoot+"/out/host_release/obj/third_party/angle/libGLESv2_static.lib"),
             };
         });
         np.Libraries.Add(IsWindows, c =>
-
-                new StaticLibrary(windowsSkiaBuild+"/libEGL.dll.lib"),
-                new StaticLibrary(windowsSkiaBuild+"/libGLESv2.dll.lib"),
-
-                new SystemLibrary("Opengl32.lib"),
+                new SystemLibrary("d3d9.lib"),
+                new SystemLibrary("gdi32.lib"),
-        np.SupportFiles.Add(c => IsWindows(c), new[] {
-                new DeployableFile(windowsSkiaBuild + "/libEGL.dll"),
-                new DeployableFile(windowsSkiaBuild + "/libEGL.dll.pdb"),
-                new DeployableFile(windowsSkiaBuild + "/libGLESv2.dll"),
-                new DeployableFile(windowsSkiaBuild + "/libGLESv2.dll.pdb"),
-            }
-        );
         np.Libraries.Add(IsMac, c =>
         {
             return new PrecompiledLibrary[]

engine/README.md

 ```
 
 Apply the following diff:
+modify flutter/third_party/txt/BUILD.gn
 ```
 --- a/third_party/txt/BUILD.gn
 +++ b/third_party/txt/BUILD.gn
 +}
 ```
 
+modify third_party/angnle/BUILD.gn
+```
+diff --git a/BUILD.gn b/BUILD.gn
+index 06bf3bbbe..1b51a32de 100644
+--- a/BUILD.gn
++++ b/BUILD.gn
+@@ -1252,3 +1252,18 @@ if (!is_component_build && is_android &&
+     ]
+   }
+ }
++
++angle_static_library("angle_lib"){
++  complete_static_lib = true
++
++  deps = [
++    ":libANGLE",
++    ":libANGLE_base", 
++    ":angle_system_utils",
++    ":angle_version",
++  ]
++
++  public_deps = [
++    ":includes",
++  ]
++}
+```
+
 
 update `out\host_debug_unopt\args.gn`
 ```
 cd engine/src
 python ./flutter/tools/gn --unoptimized
 ninja -C out\host_debug_unopt flutter/third_party/txt:txt_lib
+ninja -C out\host_debug_unopt third_party/angle:angle_lib
+ninja -C out\host_debug_unopt  third_party/angle:libEGL_static
-
-### Build Skia
-1. Install LLVM
-
-https://clang.llvm.org/get_started.html
-
-2. Build skia
-```
-cd $FLUTTER_ROOT/third_party/skia
-python2 tools/git-sync-deps
-bin/gn gen out/Debug
-```
-
-Update out/Debug/args.gn with the following content:
-```
-clang_win = "C:\Program Files\LLVM/third_party/skia"
-win_vc = "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC"
-cc = "clang"
-cxx = "clang++"
-is_debug = true
-skia_use_angle = true
-skia_use_egl = true
-extra_cflags = [
-  "/MTd",
-  "-I../../third_party/externals/angle2/include",
-]
-```
-```
-ninja -C out/Debug -k 0
-```
-Ignore this error: "lld-link: error: could not open 'EGL': no such file or directory"
 
 convert icudtl.dat to object file in flutter
 ```