Started happening on 2/26 -27 midnight
https://build.chromium.org/p/chromium.memory.fyi/builders/Windows%20Browser%20%28DrMemory%20full%29%20%281%29/builds/2760/steps/memory%20test%3A%20browser_tests_3/logs/stdio

Regression range: 378039-378114

I'll suppress it first.

### BEGIN MEMORY TOOL REPORT (error hash=#616AB0625E2A4D49#)
UNINITIALIZED READ: reading register eax
# 0 webcore_shared.dll!std::_Equal<>                                        [c:\b\depot_tools\win_toolchain\vs2013_files\4087e065abebdca6dbd0caca2910c6718d2ec67f\vc\include\xutility:2737]
# 1 webcore_shared.dll!WTF::operator==<>                                    [third_party\webkit\source\wtf\vector.h:1342]
# 2 webcore_shared.dll!blink::CSSVariableData::operator==                   [third_party\webkit\source\core\css\cssvariabledata.cpp:42]
# 3 webcore_shared.dll!blink::dataEquivalent<>                              [third_party\webkit\source\core\style\dataequivalency.h:20]
# 4 webcore_shared.dll!blink::dataEquivalent<>                              [third_party\webkit\source\core\style\dataequivalency.h:26]
# 5 webcore_shared.dll!blink::StyleVariableData::operator==                 [third_party\webkit\source\core\style\stylevariabledata.cpp:19]
# 6 webcore_shared.dll!blink::dataEquivalent<>                              [third_party\webkit\source\core\style\dataequivalency.h:20]
# 7 webcore_shared.dll!blink::dataEquivalent<>                              [third_party\webkit\source\core\style\dataequivalency.h:26]
# 8 webcore_shared.dll!blink::StyleRareInheritedData::operator==            [third_party\webkit\source\core\style\stylerareinheriteddata.cpp:233]
# 9 webcore_shared.dll!blink::DataRef<>::operator==                         [third_party\webkit\source\core\style\dataref.h:58]
#10 webcore_shared.dll!blink::ComputedStyle::operator==                     [third_party\webkit\source\core\style\computedstyle.cpp:353]
#11 webcore_shared.dll!blink::ComputedStyle::stylePropagationDiff           [third_party\webkit\source\core\style\computedstyle.cpp:196]
#12 webcore_shared.dll!blink::Element::recalcOwnStyle                       [third_party\webkit\source\core\dom\element.cpp:1748]
#13 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1699]
#14 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#15 webcore_shared.dll!blink::ShadowRoot::recalcStyle                       [third_party\webkit\source\core\dom\shadow\shadowroot.cpp:149]
#16 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1713]
#17 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#18 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1715]
#19 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#20 webcore_shared.dll!blink::ShadowRoot::recalcStyle                       [third_party\webkit\source\core\dom\shadow\shadowroot.cpp:149]
#21 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1713]
#22 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#23 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1715]
#24 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#25 webcore_shared.dll!blink::ShadowRoot::recalcStyle                       [third_party\webkit\source\core\dom\shadow\shadowroot.cpp:149]
#26 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1713]
#27 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#28 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1715]
#29 webcore_shared.dll!blink::ContainerNode::recalcChildStyle               [third_party\webkit\source\core\dom\containernode.cpp:1333]
#30 webcore_shared.dll!blink::Element::recalcStyle                          [third_party\webkit\source\core\dom\element.cpp:1715]
#31 webcore_shared.dll!blink::Document::updateStyle                         [third_party\webkit\source\core\dom\document.cpp:1852]
#32 webcore_shared.dll!blink::Document::updateLayoutTree                    [third_party\webkit\source\core\dom\document.cpp:1786]
#33 webcore_shared.dll!blink::Document::updateLayoutTreeIgnorePendingStylesheets [third_party\webkit\source\core\dom\document.cpp:2024]
#34 webcore_shared.dll!blink::Document::updateLayoutIgnorePendingStylesheets [third_party\webkit\source\core\dom\document.cpp:2029]
#35 webcore_shared.dll!blink::Element::offsetWidth                          [third_party\webkit\source\core\dom\element.cpp:630]
#36 webcore_shared.dll!blink::HTMLElementV8Internal::offsetWidthAttributeGetter [out\release\gen\blink\bindings\core\v8\v8htmlelement.cpp:468]
#37 v8.dll!v8::internal::`anonymous namespace'::Invoke                      [v8\src\execution.cc:98]
#38 v8.dll!v8::internal::Execution::Call                                    [v8\src\execution.cc:164]
#39 v8.dll!v8::internal::Execution::TryCall                                 [v8\src\execution.cc:201]