mash: Crash opening Files app
(1) build chrome and mash:all on linux on ToT @ #447052
    (revert ceb64f73f7bf1e1ae1914970c9adc455f564a1e9 locally for  Issue 686856 )
(2) run "chrome --mash"
(3) Click the app list shelf item (circle) to open the app list.
(3) Click the Files app
Expected: Files app opens and works.
Actual: Crash! Callstack below (related to app icon property conversion).

#0  gfx::internal::ImageSkiaStorage::CanRead (this=0xcdcdcdcdcdcdcdcd) at ../../ui/gfx/image/image_skia.cc:165
#1  0x00007f0106616c39 in gfx::ImageSkia::CanRead (this=0x35791b6a7a60) at ../../ui/gfx/image/image_skia.cc:515
#2  0x00007f010661727b in gfx::ImageSkia::GetRepresentation (this=0x35791b6a7a60, scale=1) at ../../ui/gfx/image/image_skia.cc:412
#3  0x00007f00fb35b088 in aura::PropertyConverter::ConvertPropertyForTransport (this=0x3579195aa220, window=0x35791b1ce260, key=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>, transport_name=0x35791ac0ad98, 
    transport_value=0x35791ac0ada0) at ../../ui/aura/mus/property_converter.cc:73
#4  0x00007f00fb37921a in aura::WindowTreeClient::OnWindowMusWillChangeProperty (this=0x3579195d8020, window=0x357919271648, key=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>)
    at ../../ui/aura/mus/window_tree_client.cc:723
#5  0x00007f00fb36c7cc in aura::WindowPortMus::OnWillChangeProperty (this=0x357919271640, key=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>) at ../../ui/aura/mus/window_port_mus.cc:431
#6  0x00007f00fb3b1694 in aura::Window::BeforePropertyChange (this=0x35791b1ce260, key=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>) at ../../ui/aura/window.cc:652
#7  0x00007f00fb3b16e6 in non-virtual thunk to aura::Window::BeforePropertyChange(void const*) () at ../../build/linux/ubuntu_precise_amd64-sysroot/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../include/c++/4.6/tuple:168
#8  0x00007f010551bad6 in ui::PropertyHandler::SetPropertyInternal (this=0x35791b1ce310, key=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>, name=0x7f00fb563991 "kAppIconKey", 
    deallocator=0x7f00fb325ed0 <aura::client::(anonymous namespace)::DeallocatorkAppIconKey(long)>, value=58794268354016, default_value=0) at ../../ui/base/class_property.cc:24
#9  0x00007f00fb3267f7 in ui::subtle::PropertyHelper::Set<gfx::ImageSkia*> (handler=0x35791b1ce310, property=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>, value=0x35791b7ae5e0)
    at ../../ui/base/class_property.h:157
#10 0x00007f00fb325955 in ui::PropertyHandler::SetProperty<gfx::ImageSkia*> (this=0x35791b1ce310, property=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>, value=0x35791b7ae5e0)
    at ../../ui/aura/client/aura_constants.cc:14
#11 0x00007f00fcf97a19 in views::(anonymous namespace)::SetIcon (window=0x35791b1ce260, key=0x7f00fb634d68 <aura::client::(anonymous namespace)::kAppIconKey_Value>, value=...) at ../../ui/views/widget/native_widget_aura.cc:94
#12 0x00007f00fcf9797d in views::NativeWidgetAura::AssignIconToAuraWindow (window=0x35791b1ce260, window_icon=..., app_icon=...) at ../../ui/views/widget/native_widget_aura.cc:129
#13 0x00007f00fcf91048 in views::DesktopNativeWidgetAura::SetWindowIcons (this=0x35791b2a4820, window_icon=..., app_icon=...) at ../../ui/views/widget/desktop_aura/desktop_native_widget_aura.cc:659
#14 0x00007f00fcf4af7e in views::Widget::UpdateWindowIcon (this=0x35791d05b460) at ../../ui/views/widget/widget.cc:830
#15 0x00007f010eb8934c in native_app_window::NativeAppWindowViews::UpdateWindowIcon (this=0x35791d172420) at ../../extensions/components/native_app_window/native_app_window_views.cc:350
#16 0x00007f0109a9a85a in extensions::AppWindow::NavigationStateChanged (this=0x35791bf52f20, source=0x35791af91e20, changed_flags=6) at ../../extensions/browser/app_window/app_window.cc:942
#17 0x00007f010266c5d6 in content::WebContentsImpl::NotifyNavigationStateChanged (this=0x35791af91e20, changed_flags=6) at ../../content/browser/web_contents/web_contents_impl.cc:1305
#18 0x00007f0102675b51 in content::WebContentsImpl::LoadStateChanged (this=0x35791af91e20, url=..., load_state=..., upload_position=0, upload_size=0) at ../../content/browser/web_contents/web_contents_impl.cc:3004
#19 0x00007f01020d1167 in content::LoaderDelegateImpl::LoadStateChanged (this=0x3579196a66a0, web_contents=0x35791af91e20, url=..., load_state=..., upload_position=0, upload_size=0)
    at ../../content/browser/loader_delegate_impl.cc:44
#20 0x00007f010207f80f in content::ResourceDispatcherHostImpl::UpdateLoadStateOnUI (loader_delegate=0x3579196a66a0, 
    infos=std::unique_ptr<std::__debug::vector<content::ResourceDispatcherHostImpl::LoadInfo, std::allocator<content::ResourceDispatcherHostImpl::LoadInfo> >> containing 0x0)
    at ../../content/browser/loader/resource_dispatcher_host_impl.cc:2514