[Device Service] Move Gamepad Blink headers to be part of the Gamepad client library

[Device Service] Move Gamepad Blink headers to be part of the Gamepad client library

This CL follows the approach of
https://codereview.chromium.org/2415083002
and moves
//third_party/WebKit/public/platform/WebGamepad.h
//third_party/WebKit/public/platform/WebGamepads.h
to
//device/gamepad/public/cpp/
and puts them in a special target to indicate that they're shared with
Blink

BUG=695012
Review-Url: https://codereview.chromium.org/2808093006
Cr-Commit-Position: refs/heads/master@{#465129}
Committed: https://chromium.googlesource.com/chromium/src/+/2f298a80296e8510f74632faa55e825cfe41ec4f

[juncai, 2017-04-11 21:08:38]

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

[commit-bot: I haz the power, 2017-04-11 21:09:16]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-11 21:15:35]

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

[commit-bot: I haz the power, 2017-04-11 21:15:36]

Dry run: Try jobs failed on following builders:
  android_clang_dbg_recipe on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_clan...)
  android_n5x_swarming_rel on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_n5x_...)
  cast_shell_linux on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/cast_shell_linu...)
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)
  ios-device-xcode-clang on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device-xcode-...)
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)
  ios-simulator-xcode-clang on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator-xco...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[juncai, 2017-04-11 21:24:40]

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

[commit-bot: I haz the power, 2017-04-11 21:25:11]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-11 21:30:38]

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

[commit-bot: I haz the power, 2017-04-11 21:30:39]

Dry run: Try jobs failed on following builders:
  android_clang_dbg_recipe on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_clan...)
  android_compile_dbg on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_comp...)
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_tsan_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[juncai, 2017-04-11 21:44:53]

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

[commit-bot: I haz the power, 2017-04-11 21:45:25]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-11 21:51:18]

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

[commit-bot: I haz the power, 2017-04-11 21:51:19]

Dry run: Try jobs failed on following builders:
  android_arm64_dbg_recipe on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_arm6...)
  android_clang_dbg_recipe on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/android_clan...)
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)
  linux_chromium_asan_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[juncai, 2017-04-11 22:22:24]

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

[commit-bot: I haz the power, 2017-04-11 22:23:23]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[juncai, 2017-04-11 22:38:34]

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

[commit-bot: I haz the power, 2017-04-11 22:39:30]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-11 23:04:15]

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

[commit-bot: I haz the power, 2017-04-11 23:04:16]

Dry run: Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_amd64-...)
  chromeos_daisy_chromium_compile_only_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromeos_daisy_...)
  linux_chromium_chromeos_ozone_rel_ng on master.tryserver.chromium.linux
(JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[juncai, 2017-04-11 23:06:26]

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

[commit-bot: I haz the power, 2017-04-11 23:07:38]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[juncai, 2017-04-11 23:55:34]

Description was changed from

==========
[Device Service] Move Gamepad Blink headers to be part of the Gamepad client
library

BUG=695012
==========

to

==========
[Device Service] Move Gamepad Blink headers to be part of the Gamepad client
library

This CL follows the approach of
https://codereview.chromium.org/2415083002
and moves
//third_party/WebKit/public/platform/WebGamepad.h
//third_party/WebKit/public/platform/WebGamepads.h
to
//device/gamepad/public/cpp/
and puts them in a special target to indicate that they're shared with
Blink

BUG=695012
==========

[commit-bot: I haz the power, 2017-04-12 02:03:29]

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

[commit-bot: I haz the power, 2017-04-12 02:03:30]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[juncai, 2017-04-12 17:24:21]

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

[commit-bot: I haz the power, 2017-04-12 17:25:18]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[juncai, 2017-04-12 18:49:05]

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

[commit-bot: I haz the power, 2017-04-12 18:50:21]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-12 21:05:53]

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

[commit-bot: I haz the power, 2017-04-12 21:05:53]

Dry run: This issue passed the CQ dry run.

[juncai, 2017-04-12 22:33:33]

juncai@chromium.org changed reviewers:
+ bajones@chromium.org, bbudge@chromium.org, dcheng@chromium.org,
haraken@chromium.org, jam@chromium.org, mattreynolds@chromium.org,
reveman@chromium.org

[juncai, 2017-04-12 22:33:34]

reveman@chromium.org: Please review changes in
//components/exo/

jam@chromium.org: Please review changes in 
//content/

mattreynolds@chromium.org: Please review changes in 
//device/gamepad/
//third_party/WebKit/Source/modules/gamepad/

bajones@chromium.org: Please review changes in 
//device/vr/

bbudge@chromium.org: Please review changes in 
//ppapi/shared_impl/

haraken@chromium.org: Please review changes in 
//third_party/WebKit/public/

dcheng@chromium.org: Please do a security review of changes in
//device/gamepad/public/interfaces/gamepad.typemap

[jam, 2017-04-12 23:02:19]

lgtm

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/pub...
File third_party/WebKit/public/platform/Platform.h (right):

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/pub...
third_party/WebKit/public/platform/Platform.h:283: virtual void
SampleGamepads(device::Gamepads& into) {}
this can just be forward declared and you don't need the include above (and the
DEPS entry)

[dcheng, 2017-04-12 23:33:27]

LGTM for mojo

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_mac.mm (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_mac.mm:26: UChar* dest,
Nit: do we need to include a header for this type? I'm not actually sure where
this type is coming from.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
File device/gamepad/public/cpp/gamepad.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
device/gamepad/public/cpp/gamepad.h:57: enum GamepadHand {
Consider making this scoped, since it looks like all the references already
fully qualify the name when they reference enumerator values.

(That would also allow the enumerator names to be shortened to kNone, kLeft,
kRight. A followup would be fine)

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
device/gamepad/public/cpp/gamepad.h:65: typedef wchar_t UChar;
Oh... I see.
Nit: prefer using over typedef

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
File device/gamepad/public/cpp/gamepads.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
device/gamepad/public/cpp/gamepads.h:19: static const size_t kItemsLengthCap =
4;
Nit: constexpr

[reveman, 2017-04-12 23:56:46]

lgtm

[mattreynolds, 2017-04-13 01:53:34]

lgtm

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_linux.cc (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_linux.cc:228: // Linker does not
like CHECK_LT(index, Gamepads::itemsLengthCap). =/
kItemsLengthCap

Also, is this comment is still true? I don't know why the linker didn't like it
before.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_linux.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_linux.h:50: int
device_fd_[Gamepads::kItemsLengthCap];
gamepads.h is getting included by gamepad_data_fetcher.h (via
gamepad_data_fetcher_manager.h and gamepad_provider.h), let's include it
explicitly

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_mac.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_mac.h:80: IOHIDElementRef
button_elements[Gamepad::kButtonsLengthCap];
Same here, gamepad.h is included by gamepad_data_fetcher.h via
gamepad_pad_state_provider.h, let's include it explicitly

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/Sou...
File third_party/WebKit/Source/modules/gamepad/GamepadDispatcher.cpp (right):

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/Sou...
third_party/WebKit/Source/modules/gamepad/GamepadDispatcher.cpp:44: DCHECK(index
< device::Gamepads::kItemsLengthCap);
DCHECK_LT

[haraken, 2017-04-13 01:54:37]

WebKit/ LGTM with jam's comment addressed.

[juncai, 2017-04-13 20:05:07]

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

[commit-bot: I haz the power, 2017-04-13 20:05:34]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-13 23:50:35]

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

[commit-bot: I haz the power, 2017-04-13 23:50:36]

Dry run: This issue passed the CQ dry run.

[juncai, 2017-04-13 23:55:52]

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_linux.cc (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_linux.cc:228: // Linker does not
like CHECK_LT(index, Gamepads::itemsLengthCap). =/
On 2017/04/13 01:53:33, mattreynolds wrote:
> kItemsLengthCap
> 
> Also, is this comment is still true? I don't know why the linker didn't like
it
> before.

The comment is still true. The linker still doesn't like CHECK_LT(index,
Gamepads::kItemsLengthCap)

Done.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_linux.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_linux.h:50: int
device_fd_[Gamepads::kItemsLengthCap];
On 2017/04/13 01:53:33, mattreynolds wrote:
> gamepads.h is getting included by gamepad_data_fetcher.h (via
> gamepad_data_fetcher_manager.h and gamepad_provider.h), let's include it
> explicitly

Done.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_mac.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_mac.h:80: IOHIDElementRef
button_elements[Gamepad::kButtonsLengthCap];
On 2017/04/13 01:53:33, mattreynolds wrote:
> Same here, gamepad.h is included by gamepad_data_fetcher.h via
> gamepad_pad_state_provider.h, let's include it explicitly

Done.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
File device/gamepad/gamepad_platform_data_fetcher_mac.mm (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/gamepad...
device/gamepad/gamepad_platform_data_fetcher_mac.mm:26: UChar* dest,
On 2017/04/12 23:33:27, dcheng wrote:
> Nit: do we need to include a header for this type? I'm not actually sure where
> this type is coming from.

It is from:
//device/gamepad/public/cpp/gamepad.h
https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
line 67
which is used at:
https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/pub...
line 106
and is from:
https://cs.chromium.org/webrtc/src/third_party/WebKit/public/platform/WebComm...
I changed its name to be UChar and move it to the gamepad.h

Added //device/gamepad/public/cpp/gamepad.h to
gamepad_platform_data_fetcher_mac.h

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
File device/gamepad/public/cpp/gamepad.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
device/gamepad/public/cpp/gamepad.h:57: enum GamepadHand {
On 2017/04/12 23:33:27, dcheng wrote:
> Consider making this scoped, since it looks like all the references already
> fully qualify the name when they reference enumerator values.
> 
> (That would also allow the enumerator names to be shortened to kNone, kLeft,
> kRight. A followup would be fine)

Done.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
device/gamepad/public/cpp/gamepad.h:65: typedef wchar_t UChar;
On 2017/04/12 23:33:27, dcheng wrote:
> Oh... I see.
> Nit: prefer using over typedef

Done.

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
File device/gamepad/public/cpp/gamepads.h (right):

https://codereview.chromium.org/2808093006/diff/130001/device/gamepad/public/...
device/gamepad/public/cpp/gamepads.h:19: static const size_t kItemsLengthCap =
4;
On 2017/04/12 23:33:27, dcheng wrote:
> Nit: constexpr

Done.

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/Sou...
File third_party/WebKit/Source/modules/gamepad/GamepadDispatcher.cpp (right):

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/Sou...
third_party/WebKit/Source/modules/gamepad/GamepadDispatcher.cpp:44: DCHECK(index
< device::Gamepads::kItemsLengthCap);
On 2017/04/13 01:53:34, mattreynolds wrote:
> DCHECK_LT

The linker doesn't like DCHECK_LT(index, device::Gamepads::kItemsLengthCap), but
DCHECK(index < device::Gamepads::kItemsLengthCap) works fine.

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/pub...
File third_party/WebKit/public/platform/Platform.h (right):

https://codereview.chromium.org/2808093006/diff/130001/third_party/WebKit/pub...
third_party/WebKit/public/platform/Platform.h:283: virtual void
SampleGamepads(device::Gamepads& into) {}
On 2017/04/12 23:02:19, jam wrote:
> this can just be forward declared and you don't need the include above (and
the
> DEPS entry)

Done.

[bbudge, 2017-04-14 00:57:33]

lgtm w/comment

https://codereview.chromium.org/2808093006/diff/150001/ppapi/shared_impl/ppb_...
File ppapi/shared_impl/ppb_gamepad_shared.cc (right):

https://codereview.chromium.org/2808093006/diff/150001/ppapi/shared_impl/ppb_...
ppapi/shared_impl/ppb_gamepad_shared.cc:17: void ConvertWebKitGamepadData(const
WebKitGamepads& webkit_data,
Is there a plan to remove the old function? Maybe a TODO?

[juncai, 2017-04-17 17:21:42]

ping bajones@, :), please review changes in 
//device/vr/

[bajones, 2017-04-17 17:31:19]

On 2017/04/17 17:21:42, juncai wrote:
> ping bajones@, :), please review changes in 
> //device/vr/

device/vr LGTM

[juncai, 2017-04-18 00:47:51]

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

[commit-bot: I haz the power, 2017-04-18 00:48:20]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-18 02:44:20]

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

[commit-bot: I haz the power, 2017-04-18 02:44:22]

Dry run: This issue passed the CQ dry run.

[juncai, 2017-04-18 03:43:52]

https://codereview.chromium.org/2808093006/diff/150001/ppapi/shared_impl/ppb_...
File ppapi/shared_impl/ppb_gamepad_shared.cc (right):

https://codereview.chromium.org/2808093006/diff/150001/ppapi/shared_impl/ppb_...
ppapi/shared_impl/ppb_gamepad_shared.cc:17: void ConvertWebKitGamepadData(const
WebKitGamepads& webkit_data,
On 2017/04/14 00:57:32, bbudge wrote:
> Is there a plan to remove the old function? Maybe a TODO?

Yes. Added TODO.

[juncai, 2017-04-18 03:44:06]

The CQ bit was checked by juncai@chromium.org

[juncai, 2017-04-18 03:44:07]

The patchset sent to the CQ was uploaded after l-g-t-m from jam@chromium.org,
dcheng@chromium.org, mattreynolds@chromium.org, haraken@chromium.org,
reveman@chromium.org, bbudge@chromium.org, bajones@chromium.org
Link to the patchset: https://codereview.chromium.org/2808093006/#ps170001
(title: "rebase and address comments")

[commit-bot: I haz the power, 2017-04-18 03:44:27]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-18 03:51:43]

CQ is committing da patch.

Bot data: {"patchset_id": 170001, "attempt_start_ts": 1492487046988140,
"parent_rev": "130cfd0cd29bdf5edba20601b496749fd954688f", "commit_rev":
"2f298a80296e8510f74632faa55e825cfe41ec4f"}

[commit-bot: I haz the power, 2017-04-18 03:51:52]

Description was changed from

==========
[Device Service] Move Gamepad Blink headers to be part of the Gamepad client
library

This CL follows the approach of
https://codereview.chromium.org/2415083002
and moves
//third_party/WebKit/public/platform/WebGamepad.h
//third_party/WebKit/public/platform/WebGamepads.h
to
//device/gamepad/public/cpp/
and puts them in a special target to indicate that they're shared with
Blink

BUG=695012
==========

to

==========
[Device Service] Move Gamepad Blink headers to be part of the Gamepad client
library

This CL follows the approach of
https://codereview.chromium.org/2415083002
and moves
//third_party/WebKit/public/platform/WebGamepad.h
//third_party/WebKit/public/platform/WebGamepads.h
to
//device/gamepad/public/cpp/
and puts them in a special target to indicate that they're shared with
Blink

BUG=695012

Review-Url: https://codereview.chromium.org/2808093006
Cr-Commit-Position: refs/heads/master@{#465129}
Committed:
https://chromium.googlesource.com/chromium/src/+/2f298a80296e8510f74632faa55e...
==========

[commit-bot: I haz the power, 2017-04-18 03:51:54]

Committed patchset #10 (id:170001) as
https://chromium.googlesource.com/chromium/src/+/2f298a80296e8510f74632faa55e...