Fix missing ObjC framework header.

BUG=webrtc:6082
NOTRY=True

Review-Url: https://codereview.webrtc.org/2127373004
Cr-Original-Commit-Position: refs/heads/master@{#13420}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 5d3f2bae48e19451597431afdf9c118268f34b98
1 file changed