Good to know! Especially since I was just looking at using the same services/ui/public/cpp/property_type_converters.h SkBitmap converter for aura::PropertyConverter to support gfx::ImageSkia window & app icon properties.

I'll try using the more complete skia/public/interfaces/bitmap.mojom serialization code (+CC yzshen@ for guidance).
Or maybe our Mus team has a better idea (it might help to tackle  Issue 655874 , +CC rjkroege@ for any thoughts).

(I can't repro on my local build at the moment, I get crashes earlier when trying to navigate Chrome)

You won't be able to test this specific use case (VPNs) in mash until I land https://codereview.chromium.org/2510083006/ and a follow-up CL. But there should be a way to open other app windows.

I'll post an example app with a non-RGBA8888 icon once I have a build that doesn't crash.

Yuzhu pointed me at this example for using mojo struct serialization code (thanks!):
  https://codesearch.chromium.org/chromium/src/cc/ipc/cc_serialization_perftest.cc?l=123

Hmm, I crash when navigating to about:extensions to try loading a test app:

Received signal 11 <unknown> 000000000000
#0 0x7f3bb43ede8e base::debug::StackTrace::StackTrace()
#1 0x7f3bb43ed9cf base::debug::(anonymous namespace)::StackDumpSignalHandler()
#2 0x7f3bb480a330 <unknown>
#3 0x7f3b90cb1a4f <unknown>
#4 0x7f3b90cada47 <unknown>
#5 0x7f3b90cb481f <unknown>
#6 0x7f3bac2bcfdd gl::GLApiBase::glClearFn()
#7 0x7f3bac5a9e3b gpu::gles2::GLES2DecoderImpl::DoClear()
#8 0x7f3bac56f649 gpu::gles2::GLES2DecoderImpl::HandleClear()
#9 0x7f3bac5d6ed2 gpu::gles2::GLES2DecoderImpl::DoCommandsImpl<>()
#10 0x7f3bac5a2235 gpu::gles2::GLES2DecoderImpl::DoCommands()
#11 0x7f3bac5239fb gpu::CommandParser::ProcessCommands()
#12 0x7f3bac526787 gpu::CommandExecutor::PutChanged()
#13 0x7f3bac7a38d8 gpu::GpuCommandBufferStub::PutChanged()
#14 0x7f3bac736765 _ZN4base8internal13FunctorTraitsIMN3gpu22InProcessCommandBufferEFvvEvE6InvokeIPS3_JEEEvS5_OT_DpOT0_

I'll take a closer look in that direction next week.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853

commit e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853
Author: msw <msw@chromium.org>
Date: Tue Nov 22 00:19:12 2016

Use mojo [de]serialization for SkBitmap property type conversion.

Removes this separate [de]serialization pattern.
Expands support beyond RGBA 8888.

BUG= 666864 
TEST=Automated; crash cited in bug no longer repros.
R=tsepez@chromium.org,sky@chromium.org
TBR=tomhudson@google.com

Review-Url: https://codereview.chromium.org/2523433003
Cr-Commit-Position: refs/heads/master@{#433711}

[modify] https://crrev.com/e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853/services/ui/public/cpp/BUILD.gn
[modify] https://crrev.com/e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853/services/ui/public/cpp/DEPS
[modify] https://crrev.com/e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853/services/ui/public/cpp/property_type_converters.cc
[modify] https://crrev.com/e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853/services/ui/public/cpp/property_type_converters.h
[modify] https://crrev.com/e7bfffb17dcf8df18e8ecf78cb7ab5de6fed3853/services/ui/public/cpp/tests/property_type_converters_unittest.cc

This should be fixed, but I still can't verify (mash crashes on any nav...)
James, please let me know if you can verify my fix; thanks!

Seems to be fixed. With https://codereview.chromium.org/2513673004/ I can now open the Pulse Secure VPN config dialog without a CHECK failure. Thanks!