GitLab

PepperVideoCaptureHost::OnFrameReady makes use of kUnknownFrameRate
which was previously only included in webrtc builds.  Let's move
these constants to the header file instead, since it can be
included in both webrtc and non-webrtc builds.

Followup to https://codereview.chromium.org/955253002.

BUG=461116,463829

Review URL: https://codereview.chromium.org/973373002

Cr-Commit-Position: refs/heads/master@{#319169}