Remove flag single_hop_screenshots

Flag has been rolled out for several months and is safe to
remove along with any legacy methods and dead code.

Bug: b/351894825
Test: atest SurfaceFlinger_test
Flag: EXEMPT flag removal
Change-Id: Id6fdfc534a0bff6ff9dfb8727c08ff821bc4965a
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 114a09b..ad3106c 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -875,16 +875,10 @@
             std::optional<OutputCompositionState>& displayState,
             std::vector<std::pair<Layer*, sp<LayerFE>>>& layers);
 
-    ftl::SharedFuture<FenceResult> captureScreenshotLegacy(
-            RenderAreaBuilderVariant, GetLayerSnapshotsFunction,
-            const std::shared_ptr<renderengine::ExternalTexture>&, bool regionSampling,
-            bool grayscale, bool isProtected, bool attachGainmap,
-            const sp<IScreenCaptureListener>&);
-
     ftl::SharedFuture<FenceResult> renderScreenImpl(
             const RenderArea*, const std::shared_ptr<renderengine::ExternalTexture>&,
-            bool regionSampling, bool grayscale, bool isProtected, bool attachGainmap,
-            ScreenCaptureResults&, std::optional<OutputCompositionState>& displayState,
+            bool regionSampling, bool grayscale, bool isProtected, ScreenCaptureResults&,
+            std::optional<OutputCompositionState>& displayState,
             std::vector<std::pair<Layer*, sp<LayerFE>>>& layers);
 
     void readPersistentProperties();