From fa3d97373c264adb1468b5eacaf51245c4370979 Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Thu, 15 Aug 2024 09:33:43 +0000
Subject: Remove legacy offscreen layer tracking

This is now tracked via the layer hierarchy builder.

Flag: EXEMPT flag removal
Bug: 330785038
Test: presubmit
Change-Id: Idb49457f8c9d91cc51c0eef8e301e36ca46626e3
---
 services/surfaceflinger/Layer.cpp          |  1 -
 services/surfaceflinger/SurfaceFlinger.cpp | 38 ------------------------------
 services/surfaceflinger/SurfaceFlinger.h   | 11 ---------
 3 files changed, 50 deletions(-)

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 3ca2e5b6ec..636f7bdabf 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -317,7 +317,6 @@ void Layer::addToCurrentState() {
     if (mRemovedFromDrawingState) {
         mRemovedFromDrawingState = false;
         mFlinger->mScheduler->registerLayer(this, FrameRateCompatibility::Default);
-        mFlinger->removeFromOffscreenLayers(this);
     }
 
     for (const auto& child : mCurrentChildren) {
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d197f15249..6a91062a63 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4362,13 +4362,6 @@ void SurfaceFlinger::doCommitTransactions() {
                 l->setIsAtRoot(false);
                 mCurrentState.layersSortedByZ.remove(l);
             }
-
-            // If the layer has been removed and has no parent, then it will not be reachable
-            // when traversing layers on screen. Add the layer to the offscreenLayers set to
-            // ensure we can copy its current to drawing state.
-            if (!l->getParent()) {
-                mOffscreenLayers.emplace(l.get());
-            }
         }
         mLayersPendingRemoval.clear();
     }
@@ -4382,7 +4375,6 @@ void SurfaceFlinger::doCommitTransactions() {
         }
     }
 
-    commitOffscreenLayers();
     if (mLayerMirrorRoots.size() > 0) {
         std::deque<Layer*> pendingUpdates;
         pendingUpdates.insert(pendingUpdates.end(), mLayerMirrorRoots.begin(),
@@ -4404,17 +4396,6 @@ void SurfaceFlinger::doCommitTransactions() {
     }
 }
 
-void SurfaceFlinger::commitOffscreenLayers() {
-    for (Layer* offscreenLayer : mOffscreenLayers) {
-        offscreenLayer->traverse(LayerVector::StateSet::Drawing, [](Layer* layer) {
-            if (layer->clearTransactionFlags(eTransactionNeeded)) {
-                layer->doTransaction(0);
-                layer->commitChildList();
-            }
-        });
-    }
-}
-
 void SurfaceFlinger::invalidateLayerStack(const ui::LayerFilter& layerFilter, const Region& dirty) {
     for (const auto& [token, displayDevice] : FTL_FAKE_GUARD(mStateLock, mDisplays)) {
         auto display = displayDevice->getCompositionDisplay();
@@ -7894,7 +7875,6 @@ void SurfaceFlinger::onLayerFirstRef(Layer* layer) {
 
 void SurfaceFlinger::onLayerDestroyed(Layer* layer) {
     mNumLayers--;
-    removeHierarchyFromOffscreenLayers(layer);
     if (!layer->isRemovedFromCurrentState()) {
         mScheduler->deregisterLayer(layer);
     }
@@ -7908,24 +7888,6 @@ void SurfaceFlinger::onLayerUpdate() {
     scheduleCommit(FrameHint::kActive);
 }
 
-// WARNING: ONLY CALL THIS FROM LAYER DTOR
-// Here we add children in the current state to offscreen layers and remove the
-// layer itself from the offscreen layer list.  Since
-// this is the dtor, it is safe to access the current state.  This keeps us
-// from dangling children layers such that they are not reachable from the
-// Drawing state nor the offscreen layer list
-// See b/141111965
-void SurfaceFlinger::removeHierarchyFromOffscreenLayers(Layer* layer) {
-    for (auto& child : layer->getCurrentChildren()) {
-        mOffscreenLayers.emplace(child.get());
-    }
-    mOffscreenLayers.erase(layer);
-}
-
-void SurfaceFlinger::removeFromOffscreenLayers(Layer* layer) {
-    mOffscreenLayers.erase(layer);
-}
-
 status_t SurfaceFlinger::setGlobalShadowSettings(const half4& ambientColor, const half4& spotColor,
                                                  float lightPosY, float lightPosZ,
                                                  float lightRadius) {
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 71278764dc..282c8cf803 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -292,9 +292,6 @@ public:
     void onLayerDestroyed(Layer*);
     void onLayerUpdate();
 
-    void removeHierarchyFromOffscreenLayers(Layer* layer);
-    void removeFromOffscreenLayers(Layer* layer);
-
     // Called when all clients have released all their references to
     // this layer. The layer may still be kept alive by its parents but
     // the client can no longer modify this layer directly.
@@ -824,8 +821,6 @@ private:
     // Clears and returns the masked bits.
     uint32_t clearTransactionFlags(uint32_t mask);
 
-    void commitOffscreenLayers();
-
     static LatchUnsignaledConfig getLatchUnsignaledConfig();
     bool shouldLatchUnsignaled(const layer_state_t&, size_t numStates, bool firstTransaction) const;
     bool applyTransactionsLocked(std::vector<TransactionState>& transactions, VsyncId)
@@ -1392,12 +1387,6 @@ private:
     // Flag used to set override desired display mode from backdoor
     bool mDebugDisplayModeSetByBackdoor = false;
 
-    // A set of layers that have no parent so they are not drawn on screen.
-    // Should only be accessed by the main thread.
-    // The Layer pointer is removed from the set when the destructor is called so there shouldn't
-    // be any issues with a raw pointer referencing an invalid object.
-    std::unordered_set<Layer*> mOffscreenLayers;
-
     BufferCountTracker mBufferCountTracker;
 
     std::unordered_map<DisplayId, sp<HdrLayerInfoReporter>> mHdrLayerInfoListeners
-- 
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