Build third-party code with -Wall, build chromium_code with -Wextra on Linux

Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002 (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002 (gpu build fix for -Wall)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
https://codereview.chromium.org/1555893002/ (-Wall for linux etc)

BUG=573250

[Nico, 2015-12-29 15:25:52]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

BUG=none
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/
BUG=none
==========

[Nico, 2015-12-29 21:27:56]

thakis@chromium.org changed reviewers:
+ thestig@chromium.org

[Nico, 2015-12-29 21:27:56]

Once you land the breakpad change, I can send try jobs for this.

[Nico, 2015-12-29 23:15:45]

The CQ bit was checked by thakis@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-12-29 23:16:05]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1551753002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1551753002/40001

[commit-bot: I haz the power, 2015-12-29 23:36:20]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-12-29 23:36:21]

Dry run: Try jobs failed on following builders:
  android_compile_dbg on tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_comp...)

[Nico, 2015-12-30 14:53:18]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/
BUG=none
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/
BUG=573250
==========

[Nico, 2015-12-30 22:51:37]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/
BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/
https://codereview.chromium.org/1553793002/
BUG=573250
==========

[Nico, 2015-12-30 22:52:05]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/
https://codereview.chromium.org/1553793002/
BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/ (landed)
https://codereview.chromium.org/1553793002/
https://codereview.chromium.org/1551963002/
BUG=573250
==========

[Nico, 2015-12-30 22:53:26]

ptal at patch set 15, I think this is pretty close to done now.

I plan to land everything except the common.gypi / compiler/BUILD.gn change
first since that shouldn't break anything, and then land then changes that
actually make things more strict in a separate step (and probably mac-only
first, and then the rest a day later or so)

https://codereview.chromium.org/1551753002/diff/200001/build/common.gypi
File build/common.gypi (left):

https://codereview.chromium.org/1551753002/diff/200001/build/common.gypi#oldc...
build/common.gypi:3160: '-Wsign-compare',
See below why this is no longer needed (this will also help with making pdfium
chromium_code on linux with gyp, finally)

https://codereview.chromium.org/1551753002/diff/200001/build/common.gypi#oldc...
build/common.gypi:3753: '-Wsign-compare',
We don't need this anymore because -Wsign-compare is part of -Wextra for clang,
so it's on now.

https://codereview.chromium.org/1551753002/diff/200001/components/nacl/render...
File components/nacl/renderer/plugin/plugin.gypi (left):

https://codereview.chromium.org/1551753002/diff/200001/components/nacl/render...
components/nacl/renderer/plugin/plugin.gypi:37: '-Wno-unused-parameter', # be a
bit stricter to match NaCl flags.
This had no effect, because -Wunused-parameter is in -Wextra, and that wasn't
on. Now that it _is_ on, we can't pass this, since this target includes base
headers, and those aren't -Wunused-parameter clean (nor should they be).

(this flag wasn't in the corresponding .gn file)

[dcheng, 2015-12-30 23:30:19]

dcheng@chromium.org changed reviewers:
+ dcheng@chromium.org

[dcheng, 2015-12-30 23:30:20]

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
File base/allocator/allocator.gyp (right):

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
base/allocator/allocator.gyp:294: # typedefs.
Isn't our copy of tcmalloc a fork? Can we fix these, or is it not worth it?

[Nico, 2015-12-30 23:53:51]

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
File base/allocator/allocator.gyp (right):

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
base/allocator/allocator.gyp:294: # typedefs.
On 2015/12/30 23:30:19, dcheng wrote:
> Isn't our copy of tcmalloc a fork? Can we fix these, or is it not worth it?

We could, but I try to not make the diff larger than necessary.

[Lei Zhang, 2015-12-30 23:53:59]

You can probably easily land the non-third-party .cc/.h files in a separate CL,
while waiting for all the dependencies / finding more surprises.

[dcheng, 2015-12-30 23:54:02]

lgtm

[Nico, 2015-12-30 23:59:58]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/ (landed)
https://codereview.chromium.org/1553793002/
https://codereview.chromium.org/1551963002/
BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/ (landed)
https://codereview.chromium.org/1553793002/
https://codereview.chromium.org/1556753002/
BUG=573250
==========

[Nico, 2015-12-31 00:00:28]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/ (landed)
https://codereview.chromium.org/1553793002/
https://codereview.chromium.org/1556753002/
BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/ (landed)
https://codereview.chromium.org/1553793002/ (landed)
https://codereview.chromium.org/1556753002/
BUG=573250
==========

[Lei Zhang, 2015-12-31 00:07:37]

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
File base/allocator/allocator.gyp (right):

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
base/allocator/allocator.gyp:294: # typedefs.
On 2015/12/30 23:53:51, Nico wrote:
> On 2015/12/30 23:30:19, dcheng wrote:
> > Isn't our copy of tcmalloc a fork? Can we fix these, or is it not worth it?
> 
> We could, but I try to not make the diff larger than necessary.

It looks like https://github.com/gperftools/gperftools/tree/master/src has
recent-ish commits. Perhaps file a bug to bring in a more recent tcmalloc and
eventually get rid of these?

https://codereview.chromium.org/1551753002/diff/280001/third_party/android_pr...
File third_party/android_protobuf/BUILD.gn (right):

https://codereview.chromium.org/1551753002/diff/280001/third_party/android_pr...
third_party/android_protobuf/BUILD.gn:7: if (is_clang) {
No if statement since the gyp version has these in a cflags block and not a
clang_warning_flags block?

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
File third_party/ocmock/BUILD.gn (right):

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
third_party/ocmock/BUILD.gn:13: cflags = [ "-Wno-semicolon-before-method-body" ]
Should this have an "if (is_clang)", like third_party/mach_override/BUILD.gn?

[Nico, 2015-12-31 02:44:17]

Thanks!

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
File base/allocator/allocator.gyp (right):

https://codereview.chromium.org/1551753002/diff/280001/base/allocator/allocat...
base/allocator/allocator.gyp:294: # typedefs.
On 2015/12/31 00:07:37, Lei Zhang wrote:
> On 2015/12/30 23:53:51, Nico wrote:
> > On 2015/12/30 23:30:19, dcheng wrote:
> > > Isn't our copy of tcmalloc a fork? Can we fix these, or is it not worth
it?
> > 
> > We could, but I try to not make the diff larger than necessary.
> 
> It looks like https://github.com/gperftools/gperftools/tree/master/src has
> recent-ish commits. Perhaps file a bug to bring in a more recent tcmalloc and
> eventually get rid of these?

From what I understand, that tcmalloc is completely separate from
google-internal tcmalloc. I'm not sure if we want  to depend on that?

https://codereview.chromium.org/1551753002/diff/280001/third_party/android_pr...
File third_party/android_protobuf/BUILD.gn (right):

https://codereview.chromium.org/1551753002/diff/280001/third_party/android_pr...
third_party/android_protobuf/BUILD.gn:7: if (is_clang) {
On 2015/12/31 00:07:37, Lei Zhang wrote:
> No if statement since the gyp version has these in a cflags block and not a
> clang_warning_flags block?

Done, good point, thanks.

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
File third_party/ocmock/BUILD.gn (right):

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
third_party/ocmock/BUILD.gn:13: cflags = [ "-Wno-semicolon-before-method-body" ]
On 2015/12/31 00:07:37, Lei Zhang wrote:
> Should this have an "if (is_clang)", like third_party/mach_override/BUILD.gn?

Doesn't matter either way, this is only build on is_mac || is_ios (see line 5),
and these always use clang

[Lei Zhang, 2015-12-31 02:56:59]

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
File third_party/ocmock/BUILD.gn (right):

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
third_party/ocmock/BUILD.gn:13: cflags = [ "-Wno-semicolon-before-method-body" ]
On 2015/12/31 02:44:17, Nico wrote:
> On 2015/12/31 00:07:37, Lei Zhang wrote:
> > Should this have an "if (is_clang)", like
third_party/mach_override/BUILD.gn?
> 
> Doesn't matter either way, this is only build on is_mac || is_ios (see line
5),
> and these always use clang

Shouldn't mach_override have the same assertion and drop the if, since it's mac
only as well? Just asking for consistency.

[Lei Zhang, 2015-12-31 02:57:19]

and lgtm!

[Nico, 2015-12-31 03:05:58]

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
File third_party/ocmock/BUILD.gn (right):

https://codereview.chromium.org/1551753002/diff/280001/third_party/ocmock/BUI...
third_party/ocmock/BUILD.gn:13: cflags = [ "-Wno-semicolon-before-method-body" ]
On 2015/12/31 02:56:59, Lei Zhang wrote:
> On 2015/12/31 02:44:17, Nico wrote:
> > On 2015/12/31 00:07:37, Lei Zhang wrote:
> > > Should this have an "if (is_clang)", like
> third_party/mach_override/BUILD.gn?
> > 
> > Doesn't matter either way, this is only build on is_mac || is_ios (see line
> 5),
> > and these always use clang
> 
> Shouldn't mach_override have the same assertion and drop the if, since it's
mac
> only as well? Just asking for consistency.

I agree. I'll send a separate CL for that.

[Nico, 2015-12-31 16:30:27]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Depends on:
https://codereview.chromium.org/1550933002/ (landed)
https://codereview.chromium.org/1553793002/ (landed)
https://codereview.chromium.org/1556753002/
BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

BUG=573250
==========

[Nico, 2015-12-31 22:02:53]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare all code, patch set 16)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2015-12-31 22:10:29]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare all code, patch set 16)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall on mac and ios)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2015-12-31 22:14:35]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall on mac and ios)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2015-12-31 22:18:11]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2016-01-01 23:30:50]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002/ (gpu build fix)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2016-01-01 23:31:02]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002/ (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002/ (gpu build fix)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002 (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002 (gpu build fix)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2016-01-01 23:31:20]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002 (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002 (gpu build fix)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002 (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002 (gpu build fix for -Wall)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

[Nico, 2016-01-02 00:13:32]

Description was changed from

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002 (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002 (gpu build fix for -Wall)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
TODO(thakis): Land more parts

BUG=573250
==========

to

==========
Build third-party code with -Wall, build chromium_code with -Wextra on Linux

clang/win already passes -Wall for third-party code, and it finds useful
things.  Do this on other platforms too.

Build chromium_code with -Wextra.  This is already done on Mac and clang/win,
let the other platforms be consistent with that.

Landed in parts here:
https://codereview.chromium.org/1557733002 (prepare code)
https://codereview.chromium.org/1555843002 (-Wall for 3rd-party on mac and ios)
https://codereview.chromium.org/1553963002 (gpu build fix for -Wall)
https://codereview.chromium.org/1552863004 (-Wextra for chromium_code)
https://codereview.chromium.org/1555893002/ (-Wall for linux etc)

BUG=573250
==========