Merge "ASurfaceTransaction: Add setEnableBackpressure" into sc-dev am: 33216a47

                                      int8_t compatibility, int8_t changeFrameRateStrategy)

                                      __INTRODUCED_IN(31);

/**

 * Indicate whether to enable backpressure for buffer submission to a given SurfaceControl.

 *

 * By default backpressure is disabled, which means submitting a buffer prior to receiving

 * a callback for the previous buffer could lead to that buffer being "dropped". In cases

 * where you are selecting for latency, this may be a desirable behavior! We had a new buffer

 * ready, why shouldn't we show it?

 *

 * When back pressure is enabled, each buffer will be required to be presented

 * before it is released and the callback delivered

 * (absent the whole SurfaceControl being removed).

 *

 * Most apps are likely to have some sort of backpressure internally, e.g. you are

 * waiting on the callback from frame N-2 before starting frame N. In high refresh

 * rate scenarios there may not be much time between SurfaceFlinger completing frame

 * N-1 (and therefore releasing buffer N-2) and beginning frame N. This means

 * your app may not have enough time to respond in the callback. Using this flag

 * and pushing buffers earlier for server side queuing will be advantageous

 * in such cases.

 *

 * \param transaction The transaction in which to make the change.

 * \param surface_control The ASurfaceControl on which to control buffer backpressure behavior.

 * \param enableBackPressure Whether to enable back pressure.

 */

void ASurfaceTransaction_setEnableBackPressure(ASurfaceTransaction* transaction,

                                               ASurfaceControl* surface_control,

                                               bool enableBackPressure)

                                               __INTRODUCED_IN(31);

__END_DECLS

#endif // ANDROID_SURFACE_CONTROL_H