This CL was landed through the CQ:
https://codereview.chromium.org/2534633002/

But caused compiler failures:
https://findit-for-me.appspot.com/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQAsSCVdmQ3VscHJpdCIxY2hyb21pdW0vYzZhYjE0YjBhYTg3N2MzZThlODg1OTM0NjA4ZDk1ODQ5ZmY5YTFhOAw

https://build.chromium.org/p/chromium.webrtc/builders/Linux%20Builder/builds/88436

https://build.chromium.org/p/chromium.memory.full/builders/Chromium%20Linux%20MSan%20Builder/builds/3276

E.g.

[2665/2683] CXX obj/chrome/test/browser_tests/test_stats_dictionary.o
FAILED: obj/chrome/test/browser_tests/test_stats_dictionary.o 
/b/c/cipd/goma/gomacc ../../third_party/llvm-build/Release+Asserts/bin/clang++ -MMD -MF obj/chrome/test/browser_tests/test_stats_dictionary.o.d -DHAS_OUT_OF_PROC_TEST_RUNNER -DV8_DEPRECATION_WARNINGS -DENABLE_NOTIFICATIONS -DENABLE_PDF=1 -DUSE_UDEV -DUI_COMPOSITOR_IMAGE_TRANSPORT -DUSE_AURA=1 -DUSE_PANGO=1 -DUSE_CAIRO=1 -DUSE_GLIB=1 -DUSE_NSS_CERTS=1 -DUSE_X11=1 -DENABLE_TASK_MANAGER=1 -DENABLE_THEMES=1 -DUSE_PROPRIETARY_CODECS -DFULL_SAFE_BROWSING -DSAFE_BROWSING_CSD -DSAFE_BROWSING_DB_LOCAL -DCHROMIUM_BUILD -DENABLE_MEDIA_ROUTER=1 -DFIELDTRIAL_TESTING_ENABLED -DCR_CLANG_REVISION=287780-2 -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DGTEST_HAS_POSIX_RE=0 -DGTEST_LANG_CXX11=1 -DGL_GLEXT_PROTOTYPES -DUSE_GLX -DUSE_EGL -DTOOLKIT_VIEWS=1 -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_NO_STATIC_INITIALIZER -DHAVE_PTHREAD -DSK_IGNORE_DW_GRAY_FIX -DSK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS -DSK_SUPPORT_GPU=1 -DENABLE_IPC_FUZZER -DV8_USE_EXTERNAL_STARTUP_DATA -DUNIT_TEST -DUSE_LIBJPEG_TURBO=1 -DENABLE_LAYOUT_UNIT_IN_INLINE_BOXES=0 -DENABLE_OILPAN=1 -DWTF_USE_CONCATENATED_IMPULSE_RESPONSES=1 -DWTF_USE_WEBAUDIO_FFMPEG=1 -DWTF_USE_DEFAULT_RENDER_THEME=1 -DLEVELDB_PLATFORM_CHROMIUM=1 -DFEATURE_ENABLE_SSL -DFEATURE_ENABLE_VOICEMAIL -DEXPAT_RELATIVE_PATH -DGTEST_RELATIVE_PATH -DNO_MAIN_THREAD_WRAPPING -DNO_SOUND_SYSTEM -DWEBRTC_CHROMIUM_BUILD -DWEBRTC_POSIX -DWEBRTC_LINUX -DSSL_USE_OPENSSL -DHAVE_OPENSSL_SSL_H -DFEATURE_ENABLE_SSL -DNO_MAIN_THREAD_WRAPPING -I../.. -Igen -I../../build/linux/debian_wheezy_amd64-sysroot/usr/include/glib-2.0 -I../../build/linux/debian_wheezy_amd64-sysroot/usr/lib/x86_64-linux-gnu/glib-2.0/include -I../../testing/gtest/include -I../../third_party/khronos -I../../gpu -I../../third_party/libwebp -I../../third_party/ced/src -I../../third_party/icu/source/common -I../../third_party/icu/source/i18n -Igen/chrome -I../../third_party/protobuf/src -Igen/protoc_out -I../../third_party/protobuf/src -I../../skia/config -I../../skia/ext -I../../third_party/skia/include/c -I../../third_party/skia/include/config -I../../third_party/skia/include/core -I../../third_party/skia/include/effects -I../../third_party/skia/include/images -I../../third_party/skia/include/lazy -I../../third_party/skia/include/pathops -I../../third_party/skia/include/pdf -I../../third_party/skia/include/pipe -I../../third_party/skia/include/ports -I../../third_party/skia/include/utils -I../../third_party/skia/include/gpu -I../../third_party/skia/src/gpu -I../../third_party/skia/src/sksl -Igen/components/strings -Igen/components/strings -Igen/components/strings -Igen/components/strings -I../../third_party/libwebm/source -I../../third_party/boringssl/src/include -I../../build/linux/debian_wheezy_amd64-sysroot/usr/include/nss -I../../build/linux/debian_wheezy_amd64-sysroot/usr/include/nspr -Igen -I../../third_party/WebKit -Igen/third_party/WebKit -I../../v8/include -Igen/v8/include -I../../v8/include -Igen/v8/include -I../../third_party/re2/src -I../../third_party/mesa/src/include -Igen/ui/resources -Igen/ui/resources -Igen -Igen/extensions -Igen/extensions -Igen/extensions -Igen -Igen/extensions/strings -Igen/components -Igen/components -Igen/ui/views/resources -I../../testing/gmock_custom -I../../testing/gmock/include -I../../third_party/libjpeg_turbo -I../../third_party/WebKit/Source -I../../third_party/WebKit -Igen/blink -Igen/third_party/WebKit -I../../third_party/iccjpeg -I../../third_party/libpng -I../../third_party/zlib -I../../third_party/ots/include -I../../third_party/leveldatabase -I../../third_party/leveldatabase/src -I../../third_party/leveldatabase/src/include -I../../sdch/open-vcdiff/src -I../../third_party/cacheinvalidation/overrides -I../../third_party/cacheinvalidation/src -I../../third_party/webrtc_overrides -I../../testing/gtest/include -I../../third_party -I../../third_party/webrtc_overrides -I../../third_party -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -funwind-tables -fPIC -pipe -B../../third_party/binutils/Linux_x64/Release/bin -fcolor-diagnostics -fdebug-prefix-map=/mnt/data/b/c/b/Linux_Builder/src=. -m64 -march=x86-64 -pthread -Wall -Werror -Wextra -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 -fno-ident -fdata-sections -ffunction-sections -g0 --sysroot=../../build/linux/debian_wheezy_amd64-sysroot -fvisibility=hidden -Xclang -load -Xclang ../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.so -Xclang -add-plugin -Xclang find-bad-constructs -Xclang -plugin-arg-find-bad-constructs -Xclang check-ipc -Wheader-hygiene -Wstring-conversion -Wno-header-guard -Xclang -load -Xclang ../../third_party/llvm-build/Release+Asserts/lib/libBlinkGCPlugin.so -Xclang -add-plugin -Xclang blink-gc-plugin -fno-threadsafe-statics -fvisibility-inlines-hidden -std=gnu++11 -fno-rtti -fno-exceptions -c ../../chrome/browser/media/webrtc/test_stats_dictionary.cc -o obj/chrome/test/browser_tests/test_stats_dictionary.o
../../chrome/browser/media/webrtc/test_stats_dictionary.cc:26:41: error: variable 'it_value' is uninitialized when used here [-Werror,-Wuninitialized]
    iteration(TestStatsDictionary(this, it_value));
                                        ^~~~~~~~
../../chrome/browser/media/webrtc/test_stats_dictionary.cc:24:42: note: initialize the variable 'it_value' to silence this warning
    const base::DictionaryValue* it_value;
                                         ^
                                          = nullptr
../../chrome/browser/media/webrtc/test_stats_dictionary.cc:81:10: error: variable 'value' is uninitialized when used here [-Werror,-Wuninitialized]
  return value;
         ^~~~~
../../chrome/browser/media/webrtc/test_stats_dictionary.cc:79:13: note: initialize the variable 'value' to silence this warning
  bool value;
            ^
             = false
../../chrome/browser/media/webrtc/test_stats_dictionary.cc:92:10: error: variable 'value' is uninitialized when used here [-Werror,-Wuninitialized]
  return value;
         ^~~~~
../../chrome/browser/media/webrtc/test_stats_dictionary.cc:90:15: note: initialize the variable 'value' to silence this warning
  double value;
              ^
               = 0.0
3 errors generated.