launchBillingFlow()
onPurchasesUpdated()
consumeAsync()
acknowledgePurchase()
getBuyIntent()
getBuyIntentExtraParams()
startIntentSenderForResult()
Intent
onActivityResult()
getPurchases()
consumePurchase()
onResume()
queryPurchases()
PurchasesUpdatedListener
com.android.vending.billing.
PURCHASES_UPDATED
onPause()