Fixes the following issues:
1. When a surface is set, it's expected that the renderer will
notify video size + when a frame is rendered to it. This is true
even if the surface isn't changing. Right now this is achieved
by setting renderedFirstFrame to false, but this is problematic
in the case that the surface isn't changing because (a) it will
force rendering of a subsequent frame to the output even when
paused, which is incorrect, and (b) isReady will return false
until this occurs.
2. When the surface really is changing, isReady can return false
until the first frame has been rendered into the new surface, which
will break seamless surface switching. This change allows isReady
to return true up to allowedJoiningTimeMs for this case.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=154171111
fb88087ac4