We have continuous failures on Win Beta, MAc Beta and Linux Beta with a different Log:

Link to Builder:
===============
Windows:
********
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5383
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5384

Mac:
****
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/mac%20beta/builds/5461
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/mac%20beta/builds/5462

Linux:
******
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/precise64%20beta/builds/4637
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/precise64%20beta/builds/4638

Link to Log File:
=================
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5383/steps/compile/logs/stdio
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/mac%20beta/builds/5461/steps/compile/logs/stdio
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/precise64%20beta/builds/4637/steps/compile/logs/stdio

Error from the Log:
===================
FAILED: obj/third_party/WebKit/Source/core/css/css_2/SelectorChecker.obj 
ninja -t msvc -e environment.x64 -- "C:\b\depot_tools\win_toolchain\vs_files\d5dc33b15d1b2c086f2f6632e2fd15882f80dbd3\VC\bin\amd64/cl.exe" /nologo /showIncludes /FC @obj/third_party/WebKit/Source/core/css/css_2/SelectorChecker.obj.rsp /c ../../third_party/WebKit/Source/core/css/SelectorChecker.cpp /Foobj/third_party/WebKit/Source/core/css/css_2/SelectorChecker.obj /Fd"obj/third_party/WebKit/Source/core/css/css_2_cc.pdb"
c:\b\build\slave\win_beta\build\src\third_party\webkit\source\core\css\selectorchecker.cpp(450): error C2196: case value '5' already used

Suspecting the below change could be the possible culprit, @ kochi: Assigning to you, kindly request you to please take a look into it.

Change URL: https://chromium.googlesource.com/chromium/src/+/136e6bae2344ec661fb566a1740ad1ef4570351d

Note: The first reported build failure was observed only on Windows, Second failure updated in this comment is seen on Windows, mac and linux OS with the same log file.

Updating the summary as well.

Thanks.!

Taking a look.  SelectorChecker.cpp change is mine.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5c81a6afca093ccd23046188ee231bba4b3f4c84

commit 5c81a6afca093ccd23046188ee231bba4b3f4c84
Author: kochi <kochi@chromium.org>
Date: Mon Nov 28 10:16:32 2016

Fix build on 2924 branch

3 Merges for  crbug.com/633007  on M56 branch (2924) had a glich
that caused compile error.

This fixes the compilation error.

TBR=tkent@chromium.org
NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
BUG= 633007 ,  668933 

Review-Url: https://codereview.chromium.org/2533743002
Cr-Commit-Position: refs/branch-heads/2924@{#110}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}

[modify] https://crrev.com/5c81a6afca093ccd23046188ee231bba4b3f4c84/third_party/WebKit/Source/core/css/SelectorChecker.cpp

I just committed the fix for SelectorChecker.cpp breakage, but not sure
about the original one (internal compiler error).

I see similar failure on win beta for official.desktop.continuous.

Link to Builder:
===============
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5388

Link to Log File:
=================
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5388/steps/compile/logs/stdio

Error from the Log:
===================
FAILED: mojo_js_integration_tests.exe mojo_js_integration_tests.exe.pdb 
C:/b/depot_tools/python276_bin/python.exe ../../build/toolchain/win/tool_wrapper.py link-wrapper environment.x64 False link.exe /nologo /OUT:./mojo_js_integration_tests.exe /PDB:./mojo_js_integration_tests.exe.pdb @./mojo_js_integration_tests.exe.rsp
c:\b\build\slave\win_beta\build\src\v8\src\heap\heap.h(487) : fatal error C1001: An internal error has occurred in the compiler.
(compiler file 'f:\dd\vctools\compiler\utc\src\p2\main.c', line 255)
 To work around this problem, try simplifying or changing the program near the locations listed above.
Please choose the Technical Support command on the Visual C++ 
 Help menu, or open the Technical Support help file for more information

CC ing today chromium sheriffs, could you please take a look on original issue and update #7?

Build 5389 passed, so seems unrelated, possibly some builder flakiness.

Below beta builds for Win/mac/linux have no failures and are green. 

Build URL's:
============
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5410
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/mac%20beta/builds/5494
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/precise64%20beta/builds/4648

Marking the issue as verified 

Re-opening this bug as  Win Beta build failed.
Build Url:
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5418
Log:
https://uberchromegw.corp.google.com/i/official.desktop.continuous/builders/win%20beta/builds/5418/steps/compile/logs/stdio

Error:
FAILED: mojo_js_unittests.exe mojo_js_unittests.exe.pdb 
C:/b/depot_tools/python276_bin/python.exe ../../build/toolchain/win/tool_wrapper.py link-wrapper environment.x64 False link.exe /nologo /OUT:./mojo_js_unittests.exe /PDB:./mojo_js_unittests.exe.pdb 

My CL doesn't have anything to this failure.

Latest beta builds compiled successfully. Marking the issue as verified again. 

Log displayed in comment #11 seems to different as that in comment# 2 which was actually fixed in this bug. Will raise a new issue if seen fresh instances of the issue reported in comment#11.

Thanks.!