horo@ suggested it could be this change, https://chromium.googlesource.com/chromium/src/+/8d31bac41bbabd01f14eff89f0fc37cd9016c225

which confuses me because it didn't touch any of the files related to that test.
+brian, does something in that change looks like it could cause this?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f3f23433d9db7b305ae57ae67a215477a5ffa162

commit f3f23433d9db7b305ae57ae67a215477a5ffa162
Author: horo <horo@chromium.org>
Date: Mon Oct 03 23:45:59 2016

Revert of cc/blimp: Add a LayerTreeHostRemote implementation. (patchset #16 id:300001 of https://codereview.chromium.org/2362073002/ )

Reason for revert:
cc_unittests on Mac-10.9 failing on chromium.mac/Mac10.9 Tests (dbg)
BUG= 652502 

BeginFrameArgsTest.Helpers (run #1):
[ RUN      ] BeginFrameArgsTest.Helpers
../../cc/output/begin_frame_args_unittest.cc:66: Failure
Value of: ::testing::PrintToString(args1)
  Actual: "64-byte object <B6-66 E8-02 01-00 00-00 F6-73 E8-02 01-00 00-00 16-00 00-00 A9-7F 00-00 E1-9C BD-01 01-00 00-00 00-00 00-00 00-00 00-00 00-00 00-00 00-00 00-00 FF-FF FF-FF FF-FF FF-FF 01-00 00-00 01-7F 00-00>"
Expected: std::string("BeginFrameArgs(NORMAL, 0, 0, -1us)")
Which is: "BeginFrameArgs(NORMAL, 0, 0, -1us)"
../../cc/output/begin_frame_args_unittest.cc:68: Failure
Value of: ::testing::PrintToString(args2)
  Actual: "64-byte object <B6-66 E8-02 01-00 00-00 F6-73 E8-02 01-00 00-00 1A-00 00-00 01-00 00-00 3B-9F BD-01 01-00 00-00 01-00 00-00 00-00 00-00 02-00 00-00 00-00 00-00 03-00 00-00 00-00 00-00 01-00 00-00 01-7F 00-00>"
Expected: std::string("BeginFrameArgs(NORMAL, 1, 2, 3us)")
Which is: "BeginFrameArgs(NORMAL, 1, 2, 3us)"
[  FAILED  ] BeginFrameArgsTest.Helpers (1 ms)

Original issue's description:
> cc/blimp: Add a LayerTreeHostRemote implementation.
>
> This sets up the framework for a LayerTreeHostRemote that implements
> the LayerTreeHost API when the compositor is running across a network
> boundary.
>
> This change only sets the framework for running/scheduling main frame
> updates and pushing the serialized state using the
> CompositorProtoStateSink. Subsequent patches will add state
> serialization.
>
> BUG= 648442 
> CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
>
> Committed: https://crrev.com/8d31bac41bbabd01f14eff89f0fc37cd9016c225
> Cr-Commit-Position: refs/heads/master@{#422555}

TBR=wez@chromium.org,dtrainor@chromium.org,danakj@chromium.org,khushalsagar@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= 648442 

Review-Url: https://codereview.chromium.org/2384333002
Cr-Commit-Position: refs/heads/master@{#422603}

[modify] https://crrev.com/f3f23433d9db7b305ae57ae67a215477a5ffa162/cc/BUILD.gn
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/compositor_proto_state.cc
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/compositor_proto_state.h
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/layer_tree_host_remote.cc
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/layer_tree_host_remote.h
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/layer_tree_host_remote_unittest.cc
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/remote_compositor_bridge.cc
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/remote_compositor_bridge.h
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/blimp/remote_compositor_bridge_client.h
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/test/fake_remote_compositor_bridge.cc
[delete] https://crrev.com/7f060555f918f54ddb5791850182aa11906183cb/cc/test/fake_remote_compositor_bridge.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0

commit bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0
Author: khushalsagar <khushalsagar@chromium.org>
Date: Tue Oct 04 02:49:06 2016

cc/blimp: Add a LayerTreeHostRemote implementation.

This sets up the framework for a LayerTreeHostRemote that implements
the LayerTreeHost API when the compositor is running across a network
boundary.

This change only sets the framework for running/scheduling main frame
updates and pushing the serialized state using the
CompositorProtoStateSink. Subsequent patches will add state
serialization.

BUG= 648442 , 652502 
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Committed: https://crrev.com/8d31bac41bbabd01f14eff89f0fc37cd9016c225
Review-Url: https://codereview.chromium.org/2362073002
Cr-Original-Commit-Position: refs/heads/master@{#422555}
Cr-Commit-Position: refs/heads/master@{#422679}

[modify] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/BUILD.gn
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/compositor_proto_state.cc
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/compositor_proto_state.h
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/layer_tree_host_remote.cc
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/layer_tree_host_remote.h
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/layer_tree_host_remote_unittest.cc
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/remote_compositor_bridge.cc
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/remote_compositor_bridge.h
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/blimp/remote_compositor_bridge_client.h
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/test/fake_remote_compositor_bridge.cc
[add] https://crrev.com/bc0b8bebb01af4c46a742a9e119a5eb39ee9aff0/cc/test/fake_remote_compositor_bridge.h