First bad build: 
https://build.chromium.org/p/chromium.fyi/builders/ClangToTMac/builds/11112/


FAILED: obj/net/net/x509_util_openssl.o 
../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF obj/net/net/x509_util_openssl.o.d -DV8_DEPRECATION_WARNINGS -DENABLE_NOTIFICATIONS -DENABLE_PEPPER_CDMS -DENABLE_PLUGINS=1 -DENABLE_PDF=1 -DENABLE_PRINTING=1 -DENABLE_BASIC_PRINTING=1 -DENABLE_PRINT_PREVIEW=1 -DENABLE_SPELLCHECK=1 -DUSE_BROWSER_SPELLCHECKER=1 -DNO_TCMALLOC -DUSE_EXTERNAL_POPUP_MENU=1 -DENABLE_WEBRTC=1 -DENABLE_EXTENSIONS=1 -DENABLE_TASK_MANAGER=1 -DENABLE_THEMES=1 -DENABLE_CAPTIVE_PORTAL_DETECTION=1 -DENABLE_SESSION_SERVICE=1 -DENABLE_PLUGIN_INSTALLATION=1 -DENABLE_SUPERVISED_USERS=1 -DENABLE_SERVICE_DISCOVERY=1 -DFULL_SAFE_BROWSING -DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DCHROMIUM_BUILD -DENABLE_MEDIA_ROUTER=1 -DFIELDTRIAL_TESTING_ENABLED -DCR_CLANG_REVISION=280645 -DCR_XCODE_VERSION=0700 -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_FORTIFY_SOURCE=2 -DCOMPONENT_BUILD -D__ASSERT_MACROS_DEFINE_VERSIONS_WITHOUT_UNDERSCORE=0 -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DDLOPEN_KERBEROS -DNET_IMPLEMENTATION -DUSE_KERBEROS -DENABLE_BUILT_IN_DNS -DENABLE_WEBSOCKETS -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -DPROTOBUF_USE_DLLS -DBORINGSSL_SHARED_LIBRARY -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_NOEXCEPT= -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -I../.. -Igen -I../../third_party/protobuf/src -Igen/protoc_out -I../../third_party/protobuf/src -I../../third_party/boringssl/src/include -I../../sdch/open-vcdiff/src -I../../third_party/zlib -I../../third_party/ced/src -I../../third_party/icu/source/common -I../../third_party/icu/source/i18n -fno-strict-aliasing -fstack-protector -fcolor-diagnostics -arch x86_64 -Wall -Werror -Wextra -Wpartial-availability -Wno-missing-field-initializers -Wno-unused-parameter -Wno-c++11-narrowing -Wno-covered-switch-default -Wno-deprecated-register -Wno-unneeded-internal-declaration -Wno-inconsistent-missing-override -Wno-shift-negative-value -Wno-undefined-var-template -Wno-nonportable-include-path -Wno-address-of-packed-member -O2 -g1 -isysroot /Applications/Xcode7.0.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk -mmacosx-version-min=10.7 -fvisibility=hidden -Wheader-hygiene -Wstring-conversion -Wexit-time-destructors -Wno-unused-function -fno-threadsafe-statics -fvisibility-inlines-hidden -std=c++11 -stdlib=libc++ -fno-rtti -fno-exceptions -include obj/net/net/precompile.h-cc -c ../../net/cert/x509_util_openssl.cc -o obj/net/net/x509_util_openssl.o
In file included from ../../net/cert/x509_util_openssl.cc:1:
In file included from /b/c/b/ClangToTMac/src/out/Release/../../build/precompile.h:32:
In file included from /b/c/b/ClangToTMac/src/third_party/llvm-build/Release+Asserts/bin/../include/c++/v1/bitset:124:
/b/c/b/ClangToTMac/src/third_party/llvm-build/Release+Asserts/bin/../include/c++/v1/string:2180:14: error: no matching function for call to '__ptr_in_range'
        if ( __ptr_in_range(&*__first, data(), data() + size()))
             ^~~~~~~~~~~~~~
../../net/cert/x509_util_openssl.cc:360:10: note: in instantiation of function template specialization 'std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::append<std::__1::__wrap_iter<unsigned char *> >' requested here
  token->append(digest.begin(), digest.end());
         ^
/b/c/b/ClangToTMac/src/third_party/llvm-build/Release+Asserts/bin/../include/c++/v1/string:2160:6: note: candidate template ignored: deduced conflicting types for parameter '_Tp' ('unsigned char' vs. 'char')
bool __ptr_in_range (const _Tp* __p, const _Tp* __first, const _Tp* __last)
     ^
1 error generated.


Some libc++ change probably.