Adjust screenshot behavior of HDR content

Cap the max amount of HDR headroom beyond which the
layer is clipped. This avoids over-dimming the SDR content
range in the resulting SDR screenshot

Test: screenshot of silkfx
Bug: 286942637
Change-Id: I67df32d9c192da18df516972ed92e9bd64063186
diff --git a/libs/renderengine/skia/SkiaRenderEngine.cpp b/libs/renderengine/skia/SkiaRenderEngine.cpp
index 5854135..fda6ea1 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.cpp
+++ b/libs/renderengine/skia/SkiaRenderEngine.cpp
@@ -86,6 +86,7 @@
 // Debugging settings
 static const bool kPrintLayerSettings = false;
 static const bool kFlushAfterEveryLayer = kPrintLayerSettings;
+static constexpr bool kEnableLayerBrightening = true;
 
 } // namespace
 
@@ -699,7 +700,8 @@
 
     // ...and compute the dimming ratio if dimming is requested
     const float displayDimmingRatio = display.targetLuminanceNits > 0.f &&
-                    maxLayerWhitePoint > 0.f && display.targetLuminanceNits > maxLayerWhitePoint
+                    maxLayerWhitePoint > 0.f &&
+                    (kEnableLayerBrightening || display.targetLuminanceNits > maxLayerWhitePoint)
             ? maxLayerWhitePoint / display.targetLuminanceNits
             : 1.f;