cc/ipc: Add missing entry in the IPC struct for cc::CompositorFrameMetadata.
cc/ipc: Add missing entry in the IPC struct for cc::CompositorFrameMetadata.

BUG=538332

Review URL: https://codereview.chromium.org/1406283012

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#356333}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk