VPLAY-12126:Dynamic restoration of latency target

[varshnie]

Reason for change:Add dynamic latency threshold restoration: tighten min/target/max back toward config defaults one step at a time when the buffer consistently maintains above danger buffer of stable sec(300s) after a rebuffering event.
Risks: Medium

Signed-off-by: varshnie varshniblue14@gmail.com

[Copilot]

Pull request overview

This PR adds dynamic restoration of LL-DASH latency thresholds after low-buffer episodes by tracking buffer health and stepping min/target/max thresholds back toward config defaults over time.

Changes:

• Extend AampLatencyMonitor with danger-buffer tracking + stepwise restoration controls (dangerBufferMs, latencyStableSec) and a notifier API (OnBufferLevelUpdate).
• Wire buffer-level notifications from fragment/chunk download success through MediaStreamContext → StreamAbstractionAAMP → PrivateInstanceAAMP → AampLatencyMonitor.
• Update config defaults/keys and expand unit test coverage for shifting, restoration, and episode-guard behavior.

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
test/utests/tests/MediaStreamContextTests/FragmentDownloadTests.cpp	Adds a default mock expectation for buffered-duration queries used by new latency-monitor notifications.
test/utests/tests/AampLatencyMonitorTests/AampLatencyMonitorTestCases.cpp	Updates/adapts tests to the new low-buffer episode model and adds restoration/episode-guard scenarios.
test/utests/fakes/FakeStreamAbstractionAamp.cpp	Adds fake stub for new latency-monitor buffer notification entry point.
test/utests/fakes/FakePrivateInstanceAAMP.cpp	Adds fake stub for new PrivateInstanceAAMP buffer notification method.
test/utests/fakes/FakeAampLatencyMonitor.cpp	Updates fake latency monitor API to OnBufferLevelUpdate.
streamabstraction.cpp	Implements forwarding helper from stream abstraction to PrivateInstanceAAMP for buffer notifications.
priv_aamp.h	Declares PrivateInstanceAAMP::NotifyBufferLevelToLatencyMonitor.
priv_aamp.cpp	Implements buffer notification forwarding to AampLatencyMonitor and populates new config fields in LL-DASH latency config.
StreamAbstractionAAMP.h	Declares StreamAbstractionAAMP::NotifyBufferLevelToLatencyMonitor with Doxygen docs.
MediaStreamContext.cpp	Emits buffer-level notifications on successful video fragment/chunk queueing.
AampLatencyMonitor.h	Extends LatencyConfig and replaces rebuffer hook with OnBufferLevelUpdate; adds restoration/episode-guard members.
AampLatencyMonitor.cpp	Implements low-buffer episode detection, stepwise restoration, and notifier wakeup behavior.
AampDefine.h	Adds defaults for latencyStableSec and dangerBufferSec.
AampConfig.h	Adds config keys for latencyStableSec and dangerBufferSec.
AampConfig.cpp	Registers new float config entries for restoration tuning.

[Vinish100]

Looks good 👍