Fix signed-unsigned-wchar build failure

Fix a build failure introduced by a new error diagnostic
(-Wsigned-unsigned-wchar) in clang that has been fixed in a newer
version of gtest and revert commit
a34bca8 which worked around it.

Change-Id: Ibe332bf65215e4722fd962540f144c435f77b2fb
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/1753067
Reviewed-by: Mark Mentovai <mark@chromium.org>
Commit-Queue: Vlad Tsyrklevich <vtsyrklevich@chromium.org>

DEPS

@@ -24,7 +24,7 @@ deps = {
       '3e50219fc4503f461b2176a9976891b28d80f9ab',
   'crashpad/third_party/gtest/gtest':
       Var('chromium_git') + '/external/github.com/google/googletest@' +
-      'da10da05c262af0a9e8fa91789a272a3dec67655',
+      'eb78ee170ac9eb21487f4d127720c060351fa8a2',
   'crashpad/third_party/gyp/gyp':
       Var('chromium_git') + '/external/gyp@' +
       '8bee09f4a57807136593ddc906b0b213c21f9014',

third_party/gtest/BUILD.gn

@@ -267,17 +267,6 @@ if (crashpad_is_in_chromium) {
   config("gmock_private_config") {
     visibility = [ ":*" ]
     include_dirs = [ "gtest/googlemock" ]
-    if (crashpad_is_clang && (crashpad_is_linux || crashpad_is_fuchsia)) {
-      cflags_cc = [
-        # This seems a bit questionable:
-        #   https://github.com/google/googletest/blob/bf6df7eaee5cfaafe2655fab143f348eba98c9af/googlemock/include/gmock/internal/gmock-internal-utils.h#L109
-        # and causes a warning/error on recent clangs (Linux/Fuchsia currently
-        # have this, other platforms don't yet).
-        # Temporarily disable this warning for building gmock tests until
-        # internal CL 263406158 lands and rolls.
-        "-Wno-signed-unsigned-wchar",
-      ]
-    }
   }
 
   config("gmock_public_config") {