Back in the gyp days, the mac/asan bots built dSYMs and sent them to swarming, where the dSYMs were used for providing symbols.

This is currently broken in several ways.

1. dSYMs are getting built but aren't in data_deps and hence aren't sent to swarming slaves.

2. In gn, the dSYM path changed (bug 699153) and we pass the wrong path to llvm-symbolizer (possible untested fix https://codereview.chromium.org/2742693004/)


The main effect of this is that stacks on e.g. https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Ftryserver.chromium.mac%2Fmac_chromium_asan_rel_ng%2F4499%2F%2B%2Frecipes%2Fsteps%2Fcontent_browsertests__with_patch_%2F0%2Fstdout don't have line numbers but ?? marks:

==11935==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x000115abbb70 bp 0x7fff54d80a30 sp 0x7fff54d80a30 T0)
==11935==The signal is caused by a WRITE memory access.
==11935==Hint: address points to the zero page.
    #0 0x115abbb6f in content::(anonymous namespace)::CrashIntentionally() ??:0:0
    #1 0x115aabf99 in content::RenderFrameImpl::PrepareRenderViewForNavigation(GURL const&, content::RequestNavigationParams const&) ??:0:0
    #2 0x115a66eeb in content::RenderFrameImpl::NavigateInternal(content::CommonNavigationParams const&, content::StartNavigationParams const&, content::RequestNavigationParams const&, std::__1::unique_ptr<content::StreamOverrideParameters, std::__1::default_delete<content::StreamOverrideParameters> >) ??:0:0
    #3 0x115a40dda in content::RenderFrameImpl::OnNavigate(content::CommonNavigationParams const&, content::StartNavigationParams const&, content::RequestNavigationParams const&) ??:0:0
    #4 0x115a4088b in bool IPC::MessageT<FrameMsg_Navigate_Meta, std::__1::tuple<content::CommonNavigationParams, content::StartNavigationParams, content::RequestNavigationParams>, void>::Dispatch<content::RenderFrameImpl, content::RenderFrameImpl, void, void (content::RenderFrameImpl::*)(content::CommonNavigationParams const&, content::StartNavigationParams const&, content::RequestNavigationParams const&)>(IPC::Message const*, content::RenderFrameImpl*, content::RenderFrameImpl*, void*, void (content::RenderFrameImpl::*)(content::CommonNavigationParams const&, content::StartNavigationParams const&, content::RequestNavigationParams const&)) ??:0:0
    #5 0x115a3ad42 in content::RenderFrameImpl::OnMessageReceived(IPC::Message const&) ??:0:0