Remove .def files from GYP and GN in webrtc/base

Remove .def files from GYP and GN in webrtc/base

This was previously done in https://webrtc-codereview.appspot.com/49969004
but was accidentally readded in https://codereview.webrtc.org/1857163003/
.def files breaks downstream since it's not a recognized file extension.

BUG=webrtc:4256
TBR=perkj@webrtc.org

Committed: https://crrev.com/c1dba730282e5e33c0b8a19bbc5ebcefc1982f18
Cr-Commit-Position: refs/heads/master@{#12243}

[kjellander_webrtc, 2016-04-05 15:31:36]

Description was changed from

==========
Remove .def files from GYP and GN in webrtc/base

This was previously done in https://webrtc-codereview.appspot.com/49969004
but was accidentally readded in https://codereview.webrtc.org/1857163003/
.def files breaks downstream since it's not a recognized file extension.

BUG=webrtc:4256
TBR=perkj@webrtc.org
==========

to

==========
Remove .def files from GYP and GN in webrtc/base

This was previously done in https://webrtc-codereview.appspot.com/49969004
but was accidentally readded in https://codereview.webrtc.org/1857163003/
.def files breaks downstream since it's not a recognized file extension.

BUG=webrtc:4256
TBR=perkj@webrtc.org

Committed:
https://chromium.googlesource.com/external/webrtc/+/c1dba730282e5e33c0b8a19bb...
==========

[kjellander_webrtc, 2016-04-05 15:31:37]

Committed patchset #1 (id:1) manually as
c1dba730282e5e33c0b8a19bbc5ebcefc1982f18 (presubmit successful).

[commit-bot: I haz the power, 2016-04-05 15:31:39]

Description was changed from

==========
Remove .def files from GYP and GN in webrtc/base

This was previously done in https://webrtc-codereview.appspot.com/49969004
but was accidentally readded in https://codereview.webrtc.org/1857163003/
.def files breaks downstream since it's not a recognized file extension.

BUG=webrtc:4256
TBR=perkj@webrtc.org

Committed:
https://chromium.googlesource.com/external/webrtc/+/c1dba730282e5e33c0b8a19bb...
==========

to

==========
Remove .def files from GYP and GN in webrtc/base

This was previously done in https://webrtc-codereview.appspot.com/49969004
but was accidentally readded in https://codereview.webrtc.org/1857163003/
.def files breaks downstream since it's not a recognized file extension.

BUG=webrtc:4256
TBR=perkj@webrtc.org

Committed: https://crrev.com/c1dba730282e5e33c0b8a19bbc5ebcefc1982f18
Cr-Commit-Position: refs/heads/master@{#12243}
==========

[commit-bot: I haz the power, 2016-04-05 15:31:40]

Patchset 1 (id:??) landed as
https://crrev.com/c1dba730282e5e33c0b8a19bbc5ebcefc1982f18
Cr-Commit-Position: refs/heads/master@{#12243}