Do you have a general plan written down for this somewhere?

In particular, which toolchain are you going to use? Is this going to use most of the _linux files or only the _posix files? (Will it even use the _posix files?) Is the ui toolkit just views? (etc)

I'm not sure about the higher level stuff, but for the lower level things, https://codereview.chromium.org/2784063002/ (config) and https://codereview.chromium.org/2692273008/ (base). I think cpu@ was going to send a note to chromium-dev about overall plan.

Toolchain will be existing clang binary (would add fuchsia libclang_rt.builtins for x86_64 and aarm64 to the package per that second CL ideally, but not necessary for now if that's inconvenient)

Will use most _posix files, but probably not _linux ones.

Thanks, sounds great, I'll await cpu's mail then.

> Toolchain will be existing clang binary

That sounds great. However, it means clang rolls can break you without us knowing about this in advance. To prevent this, you'll probably want to add a ClangToTFuchsia bot at some point.

> That sounds great. However, it means clang rolls can break you without us knowing about this in advance. To prevent this, you'll probably want to add a ClangToTFuchsia bot at some point.

Ah, right. I think it's fine to break Fuchsia for now as it's only FYI itself for now anyhow. Is ClangToTLinux a good thing to copy to make a Fuchsia one?

Yes, that's a good bot to copy. Could probably even share the slaves that that one uses.

psa to chromium-dev sent.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/324443a60943a320dc0074bdd8b4b1524493166d

commit 324443a60943a320dc0074bdd8b4b1524493166d
Author: Scott Graham <scottmg@chromium.org>
Date: Mon Jul 31 23:08:42 2017

fuchsia: Stub a few functions to get Debug linking

AmountOfAvailablePhysicalMemoryImpl isn't currently implementable as
there's no system call for it.

The GPU collection ones, there's no GPU access set up yet at all.

Bug: 706592, 707031,  743296 
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
Change-Id: Ib161bf45120ff13127ad198d57017ffc6d7c9a79
Reviewed-on: https://chromium-review.googlesource.com/592642
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490815}
[modify] https://crrev.com/324443a60943a320dc0074bdd8b4b1524493166d/base/sys_info_fuchsia.cc
[modify] https://crrev.com/324443a60943a320dc0074bdd8b4b1524493166d/gpu/config/BUILD.gn
[add] https://crrev.com/324443a60943a320dc0074bdd8b4b1524493166d/gpu/config/gpu_info_collector_fuchsia.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5ef0d852b23475c93f79b9ce25c4a89862d4800c

commit 5ef0d852b23475c93f79b9ce25c4a89862d4800c
Author: Scott Graham <scottmg@chromium.org>
Date: Mon Aug 14 19:39:55 2017

fuchsia: Fix compile of components/update_client/update_query_params.cc

Repair compile after https://chromium-review.googlesource.com/598649.

Ref: https://build.chromium.org/p/chromium.fyi/builders/Fuchsia%20%28dbg%29/builds/6184

Bug: 707031
Change-Id: I8777eba5f4f8bea9e61b2c2988d2ed9c74c12605
Reviewed-on: https://chromium-review.googlesource.com/614107
Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#494134}
[modify] https://crrev.com/5ef0d852b23475c93f79b9ce25c4a89862d4800c/components/update_client/update_query_params.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d83cbafd07629db864f055e2c28314eda9085239

commit d83cbafd07629db864f055e2c28314eda9085239
Author: Scott Graham <scottmg@chromium.org>
Date: Wed Aug 16 07:55:08 2017

fuchsia: Add helper script to build 'local' sdk

sgraham@river:/work/cr/src$ tools/fuchsia/local-sdk.py /work/fuchsia
Run: scripts/build-magenta.sh -t x86_64
...
Run: go run scripts/makesdk.go -output /tmp/tmp4CS41x/fuchsia-sdk.tgz .
Creating directory /work/cr/src/third_party/fuchsia-sdk

Script to temporarily replace third_party/fuchsia-sdk with a local build
out of the Fuchsia tree so that you can pull ToT without rolling, add
prints to Fuchsia itself, etc.

The "real" SDK can be restored by running `gclient runhooks` which will
re-download the SDK version specified in DEPS.

Bug: 707030, 707031
Change-Id: I00305378e9bb66ac3321f7031dfc97890f344404
Reviewed-on: https://chromium-review.googlesource.com/616302
Commit-Queue: Scott Graham <scottmg@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#494719}
[modify] https://crrev.com/d83cbafd07629db864f055e2c28314eda9085239/docs/fuchsia_sdk_updates.md
[add] https://crrev.com/d83cbafd07629db864f055e2c28314eda9085239/tools/fuchsia/local-sdk.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cd387344101f8f65cff0378d668d686c8080de10

commit cd387344101f8f65cff0378d668d686c8080de10
Author: Kevin Marshall <kmarshall@chromium.org>
Date: Wed Aug 16 20:02:45 2017

Fuchsia: remove calls to unported/unsupp. methods from FontCacheSkia

UI components, including font rendering, will not be ported initially
to Fuchsia. This CL ifdefs-out the portions of code which fail to
compile or link for Fuchsia headless shell builds, but the codepaths
are not meant to be executed at this point.

Bug: 707031
Change-Id: Icdedca4e109258e4416d65e07e36d81c45456444
Reviewed-on: https://chromium-review.googlesource.com/615844
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#494911}
[modify] https://crrev.com/cd387344101f8f65cff0378d668d686c8080de10/third_party/WebKit/Source/platform/fonts/skia/FontCacheSkia.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3caecccb7c26b9122ad575d5fac6cbe74cbb7c7f

commit 3caecccb7c26b9122ad575d5fac6cbe74cbb7c7f
Author: Kevin Marshall <kmarshall@chromium.org>
Date: Thu Aug 17 01:47:37 2017

Fuchsia: Create ChildProcessLauncherHelper stub.

Move POSIX sources into a conditional block, mutually exclusive with
Fuchsia sources.


Bug: 707031
Change-Id: I0d804ed6888bdac7aecee1a14ec9414734de1218
Reviewed-on: https://chromium-review.googlesource.com/616943
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495041}
[modify] https://crrev.com/3caecccb7c26b9122ad575d5fac6cbe74cbb7c7f/content/browser/BUILD.gn
[add] https://crrev.com/3caecccb7c26b9122ad575d5fac6cbe74cbb7c7f/content/browser/child_process_launcher_helper_fuchsia.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a6f5155e4cb57ee43e1dcebf1a5868bcb4e0ae62

commit a6f5155e4cb57ee43e1dcebf1a5868bcb4e0ae62
Author: Kevin Marshall <kmarshall@chromium.org>
Date: Thu Aug 17 01:50:58 2017

Fuchsia: remove font_list_fontconfig.cc from content/common:common.

Bug: 707031
Change-Id: Ifa013e131062ede750e330c97fa7b195e6540f5a
Reviewed-on: https://chromium-review.googlesource.com/617844
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: Nasko Oskov <nasko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#495044}
[modify] https://crrev.com/a6f5155e4cb57ee43e1dcebf1a5868bcb4e0ae62/content/common/BUILD.gn

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bac5c958fa5d30cacb8cf561f58f254306349881

commit bac5c958fa5d30cacb8cf561f58f254306349881
Author: James Robinson <jamesr@google.com>
Date: Sat Oct 14 01:20:09 2017

[build/fuchsia] Add flag to exe_runner to allow overriding bootdata

This is useful for booting with a locally build Fuchsia boot data
instead of the one from the SDK, especially when iterating on parts of
Fuchsia that do not change the exposed API.

Bug: 707031
Change-Id: I9c67ed167d68b09b7a2a1e7edb4e923b460e5615
Reviewed-on: https://chromium-review.googlesource.com/720203
Commit-Queue: James Robinson <jamesr@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508901}
[modify] https://crrev.com/bac5c958fa5d30cacb8cf561f58f254306349881/build/fuchsia/exe_runner.py
[modify] https://crrev.com/bac5c958fa5d30cacb8cf561f58f254306349881/build/fuchsia/runner_common.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ef23a427a2e7329a301f51fc9d9c1347b028332d

commit ef23a427a2e7329a301f51fc9d9c1347b028332d
Author: Wez <wez@chromium.org>
Date: Sat Oct 14 19:22:37 2017

Add missing parameter to BuildBootfs call in test_runner.py.

TBR: jamesr@chromium.org
Bug: 707031
Change-Id: I78db4977eece9b473b2578a8aeb30b04cef4aa55
Reviewed-on: https://chromium-review.googlesource.com/720163
Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508941}
[modify] https://crrev.com/ef23a427a2e7329a301f51fc9d9c1347b028332d/build/fuchsia/test_runner.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/268afa0fe112d514f28e310df3a95970d094909b

commit 268afa0fe112d514f28e310df3a95970d094909b
Author: James Robinson <jamesr@google.com>
Date: Tue Oct 17 02:44:13 2017

[tools/fuchsia] Update for upstream flag rename in local-sdk.py

The '--modules' flag to gen.py was renamed '--packages'.

Bug: 707031
Change-Id: I04cbae76eacf0a9c593fdf1d375c84c25fbee088
Reviewed-on: https://chromium-review.googlesource.com/721887
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: James Robinson <jamesr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509240}
[modify] https://crrev.com/268afa0fe112d514f28e310df3a95970d094909b/tools/fuchsia/local-sdk.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/63e5747e7f7c3152219cee799015fc41aee48e28

commit 63e5747e7f7c3152219cee799015fc41aee48e28
Author: James Robinson <jamesr@google.com>
Date: Wed Oct 18 20:37:00 2017

[build/fuchsia] Add flag to allow booting with specified kernel

This allows specifying a kernel to boot instead of the default one from
the SDK which is useful to pair with a local bootdata and/or run on
targets beyond the ones in the SDK.

Also removes the '--netboot' flag from the bootserver args as the
default is now stable (tftp + zedboot).

Bug: 707031
Change-Id: I4191a805b33a1cfb3e9bb5be59f8383d8b9f04e4
Reviewed-on: https://chromium-review.googlesource.com/726482
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: James Robinson <jamesr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509855}
[modify] https://crrev.com/63e5747e7f7c3152219cee799015fc41aee48e28/build/fuchsia/exe_runner.py
[modify] https://crrev.com/63e5747e7f7c3152219cee799015fc41aee48e28/build/fuchsia/runner_common.py
[modify] https://crrev.com/63e5747e7f7c3152219cee799015fc41aee48e28/build/fuchsia/test_runner.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a8c9933d76ab35db9c0e5f099b4c92e188ffe1d3

commit a8c9933d76ab35db9c0e5f099b4c92e188ffe1d3
Author: James Robinson <jamesr@google.com>
Date: Tue Oct 24 21:31:47 2017

[build/fuchsia] Add a flag to control autorun in filesystem

Sometimes it's useful to boot with a binary in the boot filesystem that
isn't run from the autorun script but is instead run from a shell (or
ssh or other mechanism). This adds a flag to the runners to control it.
It's defaulted to generating the autorun, and always set for the test
runners since it's pretty much always what you want there.

Bug: 707031
Change-Id: I14af4011d6536482f15cb92fc73d21c4fc84642b
Reviewed-on: https://chromium-review.googlesource.com/734722
Commit-Queue: James Robinson <jamesr@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511267}
[modify] https://crrev.com/a8c9933d76ab35db9c0e5f099b4c92e188ffe1d3/build/fuchsia/exe_runner.py
[modify] https://crrev.com/a8c9933d76ab35db9c0e5f099b4c92e188ffe1d3/build/fuchsia/runner_common.py
[modify] https://crrev.com/a8c9933d76ab35db9c0e5f099b4c92e188ffe1d3/build/fuchsia/test_runner.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/08e68b9785ccbc23ff46dd739ed2ec47a6b8b708

commit 08e68b9785ccbc23ff46dd739ed2ec47a6b8b708
Author: Scott Graham <scottmg@chromium.org>
Date: Thu Oct 26 02:00:13 2017

Don't gncheck #include of Linux header in cross-platform code

scottmg@around:/work/cr/src$ gn gen out/fuchgncheck --args='target_os="fuchsia" is_chromecast=true' --check
ERROR at //third_party/WebKit/Source/platform/wtf/typed_arrays/ArrayBufferContents.cpp:32:11: Include not allowed.
          ^---------------------------------------
It is not in any dependency of
  //third_party/WebKit/Source/platform/wtf:wtf
The include file is in the target(s):
  //sandbox/linux:sandbox_services
which should somehow be reachable.

Bug: 707031,  772488 
Change-Id: If109ffa0365a5ad676f1c580b4f0ea117c32eb23
Reviewed-on: https://chromium-review.googlesource.com/738819
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511692}
[modify] https://crrev.com/08e68b9785ccbc23ff46dd739ed2ec47a6b8b708/third_party/WebKit/Source/platform/wtf/typed_arrays/ArrayBufferContents.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/865a70564a128ad561085cdcb9f9960eda7ef888

commit 865a70564a128ad561085cdcb9f9960eda7ef888
Author: Sergey Ulanov <sergeyu@chromium.org>
Date: Fri Dec 01 06:39:03 2017

[fuchsia] add printing::Image::LoadMetafile() stub

libprinting.so was failing to link in component build on Fuchsia.

Bug: 707031
Change-Id: Ic9957f9184cc07c95ddca551c1abcc023f9f1102
Reviewed-on: https://chromium-review.googlesource.com/802093
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520877}
[modify] https://crrev.com/865a70564a128ad561085cdcb9f9960eda7ef888/printing/BUILD.gn
[add] https://crrev.com/865a70564a128ad561085cdcb9f9960eda7ef888/printing/image_fuchsia.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/56ac131bf1ea1646cc0b71081a92647151bf6ce2

commit 56ac131bf1ea1646cc0b71081a92647151bf6ce2
Author: Wez <wez@chromium.org>
Date: Tue Dec 05 22:03:49 2017

Fix webkit_unit_tests target to build under Fuchsia.

This requires fixing NativeValueTraitsImplTest.IDLCallbackFunction to
use ASSERT_DEATH_IF_SUPPORTED. The conditional handling for Official vs
normal builds is also removed, for simplicity.

Bug:  779820 , 707031
Change-Id: Ib2563d8b6ca792ce916d7be907956d33329e4ba4
Reviewed-on: https://chromium-review.googlesource.com/802355
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521849}
[modify] https://crrev.com/56ac131bf1ea1646cc0b71081a92647151bf6ce2/testing/buildbot/chromium.fyi.json
[modify] https://crrev.com/56ac131bf1ea1646cc0b71081a92647151bf6ce2/testing/buildbot/chromium.linux.json
[modify] https://crrev.com/56ac131bf1ea1646cc0b71081a92647151bf6ce2/testing/buildbot/waterfalls.pyl
[modify] https://crrev.com/56ac131bf1ea1646cc0b71081a92647151bf6ce2/third_party/WebKit/Source/bindings/core/v8/NativeValueTraitsImplTest.cpp
[modify] https://crrev.com/56ac131bf1ea1646cc0b71081a92647151bf6ce2/third_party/WebKit/Source/core/layout/ng/ng_length_utils_test.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/57c96393c522486902cc8e21adc1ea0bda752b09

commit 57c96393c522486902cc8e21adc1ea0bda752b09
Author: Wez <wez@chromium.org>
Date: Tue Dec 05 22:19:05 2017

Switch Fuchsia builders to use 'gn_all' in 'additional_compile_targets'.

Previously the targets to be compiled (but not run) were specified
explicitly, effectively duplicating the logic already present in the GN
build configuration files.

Bug: 707031
Change-Id: I8c6715f9f862a04a49c81030ba9d0212f0468ec9
Reviewed-on: https://chromium-review.googlesource.com/802189
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521856}
[modify] https://crrev.com/57c96393c522486902cc8e21adc1ea0bda752b09/BUILD.gn
[modify] https://crrev.com/57c96393c522486902cc8e21adc1ea0bda752b09/testing/buildbot/chromium.fyi.json
[modify] https://crrev.com/57c96393c522486902cc8e21adc1ea0bda752b09/testing/buildbot/chromium.linux.json
[modify] https://crrev.com/57c96393c522486902cc8e21adc1ea0bda752b09/testing/buildbot/gn_isolate_map.pyl
[modify] https://crrev.com/57c96393c522486902cc8e21adc1ea0bda752b09/testing/buildbot/waterfalls.pyl

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f76521f047ad8a196b626ff5850c8a829671090a

commit f76521f047ad8a196b626ff5850c8a829671090a
Author: Wez <wez@chromium.org>
Date: Wed Jan 03 21:05:45 2018

Enable more tests under Fuchsia/x64 on the waterfall.

These test binaries have no failures reported on the FYI bot over the
past 30 days.

Bug: 707031
Change-Id: I915575b4a1a31a2f1370f357140243487fe8118a
Reviewed-on: https://chromium-review.googlesource.com/848373
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526809}
[modify] https://crrev.com/f76521f047ad8a196b626ff5850c8a829671090a/testing/buildbot/chromium.linux.json
[modify] https://crrev.com/f76521f047ad8a196b626ff5850c8a829671090a/testing/buildbot/test_suite_exceptions.pyl