The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5bad341141c37fd7f74a1b0f555d7b18cc9383ca

commit 5bad341141c37fd7f74a1b0f555d7b18cc9383ca
Author: Karan Bhatia <karandeepb@chromium.org>
Date: Mon Mar 19 20:37:36 2018

Revert "ui: Add FrameMetrics histogram helpers."

This reverts commit 0465b7fed4b9d0f5d4a8636e885871b82e54f318.

Reason for revert: Breaks compile on IOS bots.

Original change's description:
> ui: Add FrameMetrics histogram helpers.
> 
> Adds a Histogram interface with two implementations. One for
> ratios with most of it's precision just above 1 and another
> for latency with higher precision near vsync intervals.
> 
> The Histogram can be queried for approximate percentiles,
> which will be useful for UKM based frame metrics.
> 
> Bug: 807463
> Change-Id: Ic50ce19eeb1804063628c09cbd1e0c30afbfd930
> Reviewed-on: https://chromium-review.googlesource.com/952534
> Commit-Queue: Brian Anderson <brianderson@chromium.org>
> Reviewed-by: Timothy Dresser <tdresser@chromium.org>
> Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#544119}

TBR=sadrul@chromium.org,brianderson@chromium.org,tdresser@chromium.org

Change-Id: I9a706e7b936abb90e6856d983d550a9272f74e24
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 807463,  823437 
Reviewed-on: https://chromium-review.googlesource.com/969226
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544148}
[modify] https://crrev.com/5bad341141c37fd7f74a1b0f555d7b18cc9383ca/ui/latency/BUILD.gn
[delete] https://crrev.com/7fb9d8f2850e74ff10c9e70301ba8d8b0842b30e/ui/latency/histograms.cc
[delete] https://crrev.com/7fb9d8f2850e74ff10c9e70301ba8d8b0842b30e/ui/latency/histograms.h
[delete] https://crrev.com/7fb9d8f2850e74ff10c9e70301ba8d8b0842b30e/ui/latency/histograms_perftest.cc
[delete] https://crrev.com/7fb9d8f2850e74ff10c9e70301ba8d8b0842b30e/ui/latency/histograms_test_common.cc
[delete] https://crrev.com/7fb9d8f2850e74ff10c9e70301ba8d8b0842b30e/ui/latency/histograms_test_common.h
[delete] https://crrev.com/7fb9d8f2850e74ff10c9e70301ba8d8b0842b30e/ui/latency/histograms_unittest.cc

FAILED: obj/ui/latency/latency_unittests_arch_executable_sources/histograms_test_common.o 
/b/build/slave/cache/goma_client/gomacc clang++ -MMD -MF obj/ui/latency/latency_unittests_arch_executable_sources/histograms_test_common.o.d -DV8_DEPRECATION_WARNINGS -DNO_TCMALLOC -DCHROMIUM_BUILD -DFIELDTRIAL_TESTING_ENABLED -DCR_XCODE_VERSION=0920 -DCR_CLANG_REVISION=\"327688-1\" -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_FORTIFY_SOURCE=2 -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DNS_BLOCK_ASSERTIONS=1 -DWEBP_EXTERN=extern -DGTEST_API_= -DGTEST_HAS_POSIX_RE=0 -DGTEST_LANG_CXX11=1 -DGTEST_HAS_TR1_TUPLE=1 -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DUCHAR_TYPE=uint16_t -DUNIT_TEST -I../.. -Igen -I../../third_party/libwebp/src -I../../third_party/googletest/src/googletest/include -I../../third_party/ced/src -I../../third_party/icu/source/common -I../../third_party/icu/source/i18n -I../../third_party/googletest/custom -I../../third_party/googletest/src/googlemock/include -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__= -fcolor-diagnostics -no-canonical-prefixes -arch armv7 -Wall -Werror -Wextra -Wimplicit-fallthrough -Wthread-safety -Wunguarded-availability -Wundeclared-selector -Wno-missing-field-initializers -Wno-unused-parameter -Wno-c++11-narrowing -Wno-covered-switch-default -Wno-unneeded-internal-declaration -Wno-inconsistent-missing-override -Wno-undefined-var-template -Wno-address-of-packed-member -Oz -fno-omit-frame-pointer -gdwarf-2 -isysroot /b/build/slave/cache/xcode_ios_9c40b.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.2.sdk -stdlib=libc++ -miphoneos-version-min=10.0 -fvisibility=hidden -Wheader-hygiene -Wstring-conversion -Wtautological-overlap-compare -std=c++14 -fno-exceptions -fno-rtti -fvisibility-inlines-hidden -c ../../ui/latency/histograms_test_common.cc -o obj/ui/latency/latency_unittests_arch_executable_sources/histograms_test_common.o
In file included from ../../ui/latency/histograms_test_common.cc:5:
../../ui/latency/histograms_test_common.h:30:5: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces]
    0,
    ^~
1 error generated.
[660/5457] STAMP obj/services/identity/public/cpp/cpp.inputdeps.stamp
[661/5457] STAMP obj/services/identity/lib.inputdeps.stamp
[662/5457] STAMP obj/services/identity/tests.inputdeps.stamp
[663/5457] STAMP obj/services/identity/public/cpp/test_support.inputdeps.stamp
[664/5457] STAMP obj/ui/latency/latency_perftests_generate_info_plist_merge.stamp
[665/5457] STAMP obj/ios/chrome/browser/web_state_list/web_state_list.inputdeps.stamp
[666/5457] ACTION //base:build_date(//build/toolchain/mac:ios_clang_arm64)
[667/4537] ACTION //components/version_info:generate_version_info_action(//build/toolchain/mac:ios_clang_arm64)
[668/4537] ACTION //remoting/ios/app:ios_remoting_app_generate_info_plist(//build/toolchain/mac:ios_clang_arm)
[669/4537] LIBTOOL-STATIC obj/ui/display/libdisplay.a
[670/4537] OBJC obj/ios/third_party/earl_grey/earl_grey_arch_shared_library_sources/GREYTestCaseInvocation.o
[671/4537] OBJCXX obj/ios/web/public/test/fakes/fakes/test_web_state_observer_util.o
[672/4537] CXX obj/ui/latency/latency/histograms.o
FAILED: obj/ui/latency/latency/histograms.o 
/b/build/slave/cache/goma_client/gomacc clang++ -MMD -MF obj/ui/latency/latency/histograms.o.d -DV8_DEPRECATION_WARNINGS -DNO_TCMALLOC -DCHROMIUM_BUILD -DFIELDTRIAL_TESTING_ENABLED -DCR_XCODE_VERSION=0920 -DCR_CLANG_REVISION=\"327688-1\" -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_FORTIFY_SOURCE=2 -DNDEBUG -DNVALGRIND -DDYNAMIC_ANNOTATIONS_ENABLED=0 -DNS_BLOCK_ASSERTIONS=1 -DWEBP_EXTERN=extern -DSK_IGNORE_LINEONLY_AA_CONVEX_PATH_OPTS -DSK_HAS_PNG_LIBRARY -DSK_HAS_WEBP_LIBRARY -DSK_SUPPORT_GPU=0 -DU_USING_ICU_NAMESPACE=0 -DU_ENABLE_DYLOAD=0 -DU_STATIC_IMPLEMENTATION -DICU_UTIL_DATA_IMPL=ICU_UTIL_DATA_FILE -DUCHAR_TYPE=uint16_t -I../.. -Igen -I../../third_party/libwebp/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/encode -I../../third_party/skia/include/gpu -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/icu/source/common -I../../third_party/icu/source/i18n -fno-strict-aliasing --param=ssp-buffer-size=4 -fstack-protector -Wno-builtin-macro-redefined -D__DATE__= -D__TIME__= -D__TIMESTAMP__= -fcolor-diagnostics -no-canonical-prefixes -arch armv7 -Wall -Werror -Wextra -Wimplicit-fallthrough -Wthread-safety -Wunguarded-availability -Wundeclared-selector -Wno-missing-field-initializers -Wno-unused-parameter -Wno-c++11-narrowing -Wno-covered-switch-default -Wno-unneeded-internal-declaration -Wno-inconsistent-missing-override -Wno-undefined-var-template -Wno-address-of-packed-member -Oz -fno-omit-frame-pointer -gdwarf-2 -isysroot /b/build/slave/cache/xcode_ios_9c40b.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.2.sdk -stdlib=libc++ -miphoneos-version-min=10.0 -fvisibility=hidden -Wheader-hygiene -Wstring-conversion -Wtautological-overlap-compare -std=c++14 -fno-exceptions -fno-rtti -fvisibility-inlines-hidden -c ../../ui/latency/histograms.cc -o obj/ui/latency/latency/histograms.o
../../ui/latency/histograms.cc:243:56: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces]
constexpr std::array<uint8_t, 6> kVSyncBucketCounts = {12, 16, 16, 16, 31, 6};
                                                       ^~~~~~~~~~~~~~~~~~~~~
                                                       {                    }
1 error generated.

 Issue 823436  has been merged into this issue.

Seems to be fixed.