Version: Chromium	51.0.2677.0 (Developer Build) (64-bit) with dcheck_always_on=1
OS: Linux

What steps will reproduce the problem?

not sure it is reproducible steps, but what I did was
(1) open spreadsheet from docs.google.com
(2) enable offline as suggested
(3)

What is the expected output? What do you see instead?

chromium crashed
[33874:33908:0314/135706:FATAL:appcache_host.cc(409)] Check failed: cache->owning_group()->manifest_url() == preferred_manifest_url_ (https://docs.google.com/offline/common/manifest?ouid=u252d6e3074428132 vs. )

(gdb) bt
#0  0x00007fffeeee5cc9 in __GI_raise (sig=sig@entry=6)
    at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1  0x00007fffeeee90d8 in __GI_abort () at abort.c:89
#2  0x00007ffff7ec06b2 in base::debug::BreakDebugger() ()
   from /usr/local/google/home/ukai/src/chromium-git/src/out.0/Release/./libbase.so
#3  0x00000000000000d3 in ?? ()
#4  0x00007ffff7ee1c0a in logging::LogMessage::~LogMessage() ()
   from /usr/local/google/home/ukai/src/chromium-git/src/out.0/Release/./libbase.so
#5  0x00007fffd5f44ec0 in ?? ()
#6  0x00003f2d211725b8 in ?? ()
#7  0x00003f2d1dc5cdf3 in ?? ()
#8  0x00007fffeef609f1 in update_vars () at tzset.c:152
#9  __tzset_parse_tz (tz=<optimized out>) at tzset.c:395
Backtrace stopped: Cannot access memory at address 0xb


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https://chromium.googlesource.com/chromium/src/+/ea2a7b919337fb796c8602f1701b60d8fa2d7f42%5E%21/webkit/appcache/appcache_host.cc