I think it was my change https://codereview.chromium.org/2831733003 . The key assertion failure seems to be:

[3488:928:0421/205118.589:FATAL:gles2_implementation_impl_autogen.h(606)] Check failed: textures[i] != 0. 
Backtrace:
	base::debug::StackTrace::StackTrace [0x0000000000621FE5+69]
	base::debug::StackTrace::StackTrace [0x0000000000621B08+24]
	logging::LogMessage::~LogMessage [0x00000000006932B0+112]
	gpu::gles2::GLES2Implementation::DeleteTextures [0x00000000194867AB+763]
	blink::DrawingBuffer::ColorBuffer::~ColorBuffer [0x000000001D38C418+712]
	blink::DrawingBuffer::ColorBuffer::`scalar deleting destructor' [0x000000001D38D377+23]
	WTF::RefCounted<blink::DrawingBuffer::ColorBuffer>::Deref [0x000000001D391526+70]
	WTF::DerefIfNotNull<blink::DrawingBuffer::ColorBuffer> [0x000000001D3894BB+27]
	 

It was in fact https://codereview.chromium.org/2831733003 , which was reverted in https://codereview.chromium.org/2841573002/ .

The reason that this wasn't caught by the tryservers is that the guard for GPU_CLIENT_DCHECK_CODE_BLOCK is wrong -- rather than checking

  #if !defined(NDEBUG) ...

it should be checking

  #if DCHECK_IS_ON() ...

Also, this happened at least on macOS too; compare:

https://build.chromium.org/p/chromium.gpu/builders/Mac%20Retina%20Debug%20%28AMD%29/builds/4067

to

https://build.chromium.org/p/chromium.gpu/builders/Mac%20Retina%20Debug%20%28AMD%29/builds/4068

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/88c1201998461775ec1c604baa77c25c8023af8c

commit 88c1201998461775ec1c604baa77c25c8023af8c
Author: kbr <kbr@chromium.org>
Date: Mon Apr 24 22:12:54 2017

Make GPU_CLIENT_DCHECK_CODE_BLOCK obey DCHECK_ALWAYS_ON.

Note that this block of #ifdefs violates the indentation guidelines,
but I'm ignoring that because the current form is more readable.

BUG= 714761 
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.android:android_optional_gpu_tests_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel

Review-Url: https://codereview.chromium.org/2837773004
Cr-Commit-Position: refs/heads/master@{#466790}

[modify] https://crrev.com/88c1201998461775ec1c604baa77c25c8023af8c/gpu/command_buffer/client/gles2_implementation.h

https://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_ng/builds/437659 verifies that this assertion is now caught on the trybots, which run with dcheck_always_on=true .

 Issue 714423  has been merged into this issue.