Resolve subtle but severe flickering in layer caching

Inconsistencies in composer state was arising from a layer exiting layer
caching. Resolve this by:

* If a layer previously had an override buffer, but now does not for the
current frame, set the surface damage region to be the entire buffer.
* If a layer is currently being skipped, then don't update the
composition type, since the validated composition type is no longer
accurate for representing the current composition type of the device.
* If a layer was previously skipped, then update in HWC the new
composition type every time.

The inconsistencies have arised from the layer caching feature
because composer implementations cache the most recent requested
composition type for each layer, but SurfaceFlinger caches the most
recent {requested, validated} type for each layer, whichever
SurfaceFlinger sees last. So if we forced client composition, then
untoggled client composition, and if hwc was device compositing the
layer during validate instead of client compositing because hwc ignored
the layer, then SF caches DEVICE composition, but hwc caches CLIENT
composition internally. SF then doesn't update the layer's composition
type because it cached DEVICE composition, but hwc never displays the
layer because hwc cached CLIENT composition, and typical hwc
implementations never attempt to read from client composited layers.

Bug: 187193705
Test: libcompositionengine_test
Test: enable layer caching and repeatedly enable and disable client
composition when pip is playing

Change-Id: I9b6890bcf3f0612e8f99f5f1642015e53d59f862

0 files changed, 0 insertions, 0 deletions