removed the requirement of GET_ACCOUNTS for API level 16 and higher

... so that user will have one less permission to grant. In AndroidManifest.xml of the app, we can specify maxSdkVersion for uses-permission.

<uses-permission android:name="android.permission.GET_ACCOUNTS" android:maxSdkVersion="15" />

Reference:
http://developer.android.com/google/gcm/client.html