1c12b818b3
RTCEAGLVideoVideo ensureGLContext has been observed to fail because the GL context is nil. This CL checks the GL context is non-nil in the ctor instead. BUG=b/62865840 Review-Url: https://codereview.webrtc.org/2991863002 Cr-Commit-Position: refs/heads/master@{#19189}