Don't delete the manifest when linking on Windows in GN

build/toolchain/win/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/win/visual_studio_version.gni")
 import("//build/toolchain/goma.gni")
 
 # Should only be running on Windows.
 assert(is_win)
 
@@ skipping 41 matching lines @@
     command = "$python_path gyp-win-tool asm-wrapper environment.x86 ml.exe \$defines \$includes /c /Fo \$out \$in"
     description = "ASM \$in"
   }
   tool("alink") {
     command = "$python_path gyp-win-tool link-wrapper environment.x86 False lib.exe /nologo /ignore:4221 /OUT:\$out @\$out.rsp"
     description = "LIB \$out"
     rspfile = "\$out.rsp"
     rspfile_content = "\$in_newline \$libflags"
   }
   tool("solink") {
-    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x86 False link.exe /nologo \$implibflag /DLL /OUT:\$dll /PDB:\$dll.pdb @\$dll.rsp && $python_path gyp-win-tool manifest-wrapper environment.x86 cmd /c if exist \$dll.manifest del \$dll.manifest && $python_path gyp-win-tool manifest-wrapper environment.x86 mt.exe -nologo -manifest \$manifests -out:\$dll.manifest"
+    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x86 False link.exe /nologo \$implibflag /DLL /OUT:\$dll /PDB:\$dll.pdb @\$dll.rsp && $python_path gyp-win-tool manifest-wrapper environment.x86 mt.exe -nologo -manifest \$manifests -out:\$dll.manifest"
     description = "LINK(DLL) \$dll"
     restat = "1"
     rspfile = "\$dll.rsp"
     rspfile_content = "\$libs \$in_newline \$ldflags"
   }
   tool("link") {
-    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x86 False link.exe /nologo /OUT:\$out /PDB:\$out.pdb @\$out.rsp && $python_path gyp-win-tool manifest-wrapper environment.x86 cmd /c if exist \$out.manifest del \$out.manifest && $python_path gyp-win-tool manifest-wrapper environment.x86 mt.exe -nologo -manifest \$manifests -out:\$out.manifest"
+    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x86 False link.exe /nologo /OUT:\$out /PDB:\$out.pdb @\$out.rsp && $python_path gyp-win-tool manifest-wrapper environment.x86 mt.exe -nologo -manifest \$manifests -out:\$out.manifest"
     description = "LINK \$out"
     rspfile = "\$out.rsp"
     rspfile_content = "\$in_newline \$libs \$ldflags"
   }
   tool("stamp") {
     command = stamp_command
     description = "STAMP \$out"
   }
   tool("copy") {
     command = copy_command
@@ skipping 31 matching lines @@
     command = "$python_path gyp-win-tool asm-wrapper environment.x64 ml.exe \$defines \$includes /c /Fo \$out \$in"
     description = "ASM \$in"
   }
   tool("alink") {
     command = "$python_path gyp-win-tool link-wrapper environment.x64 False lib.exe /nologo /ignore:4221 /OUT:\$out @\$out.rsp"
     description = "LIB \$out"
     rspfile = "\$out.rsp"
     rspfile_content = "\$in_newline \$libflags"
   }
   tool("solink") {
-    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x64 False link.exe /nologo \$implibflag /DLL /OUT:\$dll /PDB:\$dll.pdb @\$dll.rsp && $python_path gyp-win-tool manifest-wrapper environment.x64 cmd /c if exist \$dll.manifest del \$dll.manifest && $python_path gyp-win-tool manifest-wrapper environment.x64 mt.exe -nologo -manifest \$manifests -out:\$dll.manifest"
+    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x64 False link.exe /nologo \$implibflag /DLL /OUT:\$dll /PDB:\$dll.pdb @\$dll.rsp && $python_path gyp-win-tool manifest-wrapper environment.x64 mt.exe -nologo -manifest \$manifests -out:\$dll.manifest"
     description = "LINK(DLL) \$dll"
     restat = "1"
     rspfile = "\$dll.rsp"
     rspfile_content = "\$libs \$in_newline \$ldflags"
   }
   tool("link") {
-    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x64 False link.exe /nologo /OUT:\$out /PDB:\$out.pdb @\$out.rsp && $python_path gyp-win-tool manifest-wrapper environment.x64 cmd /c if exist \$out.manifest del \$out.manifest && $python_path gyp-win-tool manifest-wrapper environment.x64 mt.exe -nologo -manifest \$manifests -out:\$out.manifest"
+    command = "cmd /c $python_path gyp-win-tool link-wrapper environment.x64 False link.exe /nologo /OUT:\$out /PDB:\$out.pdb @\$out.rsp && $python_path gyp-win-tool manifest-wrapper environment.x64 mt.exe -nologo -manifest \$manifests -out:\$out.manifest"
     description = "LINK \$out"
     rspfile = "\$out.rsp"
     rspfile_content = "\$in_newline \$libs \$ldflags"
   }
   tool("stamp") {
     command = stamp_command
     description = "STAMP \$out"
   }
   tool("copy") {
     command = copy_command
     description = "COPY \$in \$out"
   }
 
   # When invoking this toolchain not as the default one, these args will be
   # passed to the build. They are ignored when this is the default toolchain.
   toolchain_args() {
     cpu_arch = "x64"
     # Normally the build config resets the CPU architecture to 32-bits. Setting
     # this flag overrides that behavior.
     force_win64 = true
   }
 }