Link to Builder:
================
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20trunk/builds/58074
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20trunk/builds/58075

Link to Log File:
=================
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20trunk/builds/58074/steps/compile/logs/stdio
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20trunk/builds/58075/steps/compile/logs/stdio

Error from the log:
===================
FAILED: obj/third_party/WebKit/Source/core/editing/editing_0/Editor.obj 
ninja -t msvc -e environment.x64 -- "C:\b\depot_tools\win_toolchain\vs_files\d3cb0e37bdd120ad0ac4650b674b09e81be45616\VC\bin\amd64/cl.exe" /nologo /showIncludes /FC @obj/third_party/WebKit/Source/core/editing/editing_0/Editor.obj.rsp /c ../../third_party/WebKit/Source/core/editing/Editor.cpp /Foobj/third_party/WebKit/Source/core/editing/editing_0/Editor.obj /Fd"obj/third_party/WebKit/Source/core/editing/editing_0_cc.pdb"
c:\b\build\slave\win_trunk\build\src\third_party\webkit\source\core\editing\editor.cpp(743): error C2065: 'endingSelection': undeclared identifier

Suspecting below change could be a possible culprit:

https://chromium.googlesource.com/chromium/src/+/d57cc7528932df35ce4a7d56f7cfc9dc380e5a09

@ xiaochengh: Assigning to you, kindly take a look into it.