diff --git .gn .gn
index b0565e5..4fd1771 100644
--- .gn
+++ .gn
@@ -259,6 +259,7 @@ exec_script_whitelist =
       # in the Chromium repo outside of //build.
       "//android_webview/BUILD.gn",
       "//build_overrides/build.gni",
+      "//cef/BUILD.gn",
       "//chromeos/BUILD.gn",
 
       # TODO(dgn): Layer violation but breaks the build otherwise, see
diff --git BUILD.gn BUILD.gn
index d783ebe..ae5e8d1 100644
--- BUILD.gn
+++ BUILD.gn
@@ -282,6 +282,7 @@ group("both_gn_and_gyp") {
     # and whether there should be other targets that are iOS-only and missing.
     deps += [
       "//cc:cc_unittests",
+      "//cef",
       "//chrome/test:telemetry_perf_unittests",
       "//chrome/test:unit_tests",
       "//components:components_browsertests",
diff --git build/config/win/visual_studio_version.gni build/config/win/visual_studio_version.gni
index 982fbe8..e757be46 100644
--- build/config/win/visual_studio_version.gni
+++ build/config/win/visual_studio_version.gni
@@ -12,9 +12,8 @@ declare_args() {
   # Currently always "2015".
   visual_studio_version = ""
 
-  # Directory of the Windows driver kit. If visual_studio_path is empty, this
-  # will be auto-filled.
-  wdk_path = ""
+  # Path to Visual Studio runtime libraries.
+  visual_studio_runtime_dirs = ""
 
   # Full path to the Windows SDK, not including a backslash at the end.
   # This value is the default location, override if you have a different
@@ -28,12 +27,11 @@ if (visual_studio_path == "") {
   visual_studio_path = toolchain_data.vs_path
   windows_sdk_path = toolchain_data.sdk_path
   visual_studio_version = toolchain_data.vs_version
-  wdk_path = toolchain_data.wdk_dir
   visual_studio_runtime_dirs = toolchain_data.runtime_dirs
 } else {
   assert(visual_studio_version != "",
          "You must set the visual_studio_version if you set the path")
-  assert(wdk_path != "",
-         "You must set the wdk_path if you set the visual studio path")
-  visual_studio_runtime_dirs = []
+  assert(visual_studio_runtime_dirs != "",
+         "You must set the visual_studio_runtime_dirs if you set the visual " +
+         "studio path")
 }
diff --git build/toolchain/win/setup_toolchain.py build/toolchain/win/setup_toolchain.py
index ec60564..6e88441 100644
--- build/toolchain/win/setup_toolchain.py
+++ build/toolchain/win/setup_toolchain.py
@@ -127,15 +127,17 @@ def _LoadToolchainEnv(cpu, sdk_dir):
                                        os.environ['GYP_MSVS_OVERRIDE_PATH'],
                                        'VC/vcvarsall.bat'))
     if not os.path.exists(script_path):
-      other_path = os.path.normpath(os.path.join(
+      script_path = os.path.normpath(os.path.join(
                                         os.environ['GYP_MSVS_OVERRIDE_PATH'],
                                         'VC/Auxiliary/Build/vcvarsall.bat'))
-      if not os.path.exists(other_path):
-        raise Exception('%s is missing - make sure VC++ tools are installed.' %
-                        script_path)
-      script_path = other_path
-    args = [script_path, 'amd64_x86' if cpu == 'x86' else 'amd64']
-    variables = _LoadEnvFromBat(args)
+    if os.path.exists(script_path):
+      args = [script_path, 'amd64_x86' if cpu == 'x86' else 'amd64']
+      variables = _LoadEnvFromBat(args)
+    else:
+      variables = []
+      for k in sorted(os.environ.keys()):
+        variables.append('%s=%s' % (str(k), str(os.environ[k])))
+      variables = '\n'.join(variables)
   return _ExtractImportantEnvironment(variables)
 
 
diff --git build/vs_toolchain.py build/vs_toolchain.py
index c5db1b24..e4f5839 100755
--- build/vs_toolchain.py
+++ build/vs_toolchain.py
@@ -74,11 +74,18 @@ def SetEnvironmentAndGetRuntimeDllDirs():
     runtime_path = os.path.pathsep.join(vs_runtime_dll_dirs)
     os.environ['PATH'] = runtime_path + os.path.pathsep + os.environ['PATH']
   elif sys.platform == 'win32' and not depot_tools_win_toolchain:
+    has_override_path = True
     if not 'GYP_MSVS_OVERRIDE_PATH' in os.environ:
+      has_override_path = False
       os.environ['GYP_MSVS_OVERRIDE_PATH'] = DetectVisualStudioPath()
     if not 'GYP_MSVS_VERSION' in os.environ:
       os.environ['GYP_MSVS_VERSION'] = GetVisualStudioVersion()
 
+    if has_override_path:
+      # Don't attempt to copy DLLs when using a custom toolchain.
+      # The DLLs should already be discoverable via the PATH env variable.
+      return None
+
     # When using an installed toolchain these files aren't needed in the output
     # directory in order to run binaries locally, but they are needed in order
     # to create isolates or the mini_installer. Copying them to the output
diff --git chrome/chrome_paks.gni chrome/chrome_paks.gni
index 811afda..8d21b5f 100644
--- chrome/chrome_paks.gni
+++ chrome/chrome_paks.gni
@@ -249,7 +249,7 @@ template("chrome_paks") {
       additional_source_patterns = invoker.additional_locale_source_patterns
     }
     input_locales = locales
-    output_dir = "${invoker.output_dir}/locales"
+    output_dir = "${invoker.output_dir}/chrome/locales"
 
     if (is_mac) {
       output_locales = locales_as_mac_outputs
diff --git chrome/installer/mini_installer/BUILD.gn chrome/installer/mini_installer/BUILD.gn
index 5d2fe25..dd08482 100644
--- chrome/installer/mini_installer/BUILD.gn
+++ chrome/installer/mini_installer/BUILD.gn
@@ -128,7 +128,7 @@ template("generate_mini_installer") {
     inputs = [
       "$chrome_dll_file",
       "$root_out_dir/chrome.exe",
-      "$root_out_dir/locales/en-US.pak",
+      "$root_out_dir/chrome/locales/en-US.pak",
       "$root_out_dir/setup.exe",
       release_file,
     ]