Ensure that LayerFECompositionState's fence is always non-null

When a solid color layer is overridden by a cached set AND the layer is
skipped due to a prior overridden layer, acquireFence must be nonnull.
Otherwise, the DisplayHardware apis will fail.

To be less error-prone, set LayerFECompositionState's acquire fence to be
Fence::NO_FENCE.

Bug: 209930535
Bug: 208780233
Test: PiP in maps app
Change-Id: Ia896419eb699903453f6f69e4b6c3527e62ec270
diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h
index 36594ea..7e605f9 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/LayerFECompositionState.h
@@ -161,7 +161,7 @@
     // The buffer and related state
     sp<GraphicBuffer> buffer;
     int bufferSlot{BufferQueue::INVALID_BUFFER_SLOT};
-    sp<Fence> acquireFence;
+    sp<Fence> acquireFence = Fence::NO_FENCE;
     Region surfaceDamage;
 
     // The handle to use for a sideband stream for this layer
diff --git a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
index 31b131a..fd584fd 100644
--- a/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/OutputLayerTest.cpp
@@ -1093,6 +1093,22 @@
                                  /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
 }
 
+TEST_F(OutputLayerWriteStateToHWCTest, overriddenSkipLayerForSolidColorDoesNotSendBuffer) {
+    mLayerFEState.compositionType = Hwc2::IComposerClient::Composition::SOLID_COLOR;
+    includeOverrideInfo();
+
+    expectGeometryCommonCalls(kOverrideDisplayFrame, kOverrideSourceCrop, kOverrideBufferTransform,
+                              kOverrideBlendMode, kSkipAlpha);
+    expectPerFrameCommonCalls(SimulateUnsupported::None, kOverrideDataspace, kOverrideVisibleRegion,
+                              kOverrideSurfaceDamage);
+    expectSetHdrMetadataAndBufferCalls();
+    expectSetCompositionTypeCall(Hwc2::IComposerClient::Composition::DEVICE);
+    EXPECT_CALL(*mLayerFE, hasRoundedCorners()).WillRepeatedly(Return(false));
+
+    mOutputLayer.writeStateToHWC(/*includeGeometry*/ true, /*skipLayer*/ true, 0,
+                                 /*zIsOverridden*/ false, /*isPeekingThrough*/ false);
+}
+
 TEST_F(OutputLayerWriteStateToHWCTest, includesOverrideInfoIfPresent) {
     mLayerFEState.compositionType = Hwc2::IComposerClient::Composition::DEVICE;
     includeOverrideInfo();