Compile components/copresence/proto/enums.proto in Android.
Compile components/copresence/proto/enums.proto in Android.

When we compile for android, g++ gets the flag "-DANDROID", and then
pre-processor removes ANDROID from IdentifyType, which causes compile errors.
To fix this, we change ANDROID to ANDROIDOS in IdentifyType.

BUG=550158

Review URL: https://codereview.chromium.org/1415533018

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#357605}

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