End-to-end plumbing for dimming SDR layers

Model here is:
* HDR luminance is set to the current display brightness
* SDR luminance is set to the current SDR white point reported by
DisplayManager

Ideally we use scene-referred white points instead, so:
* PQ is always 10k nits
* HLG is always 1k nits
* Everything else is 150-200 nits

So relative dimming thresholds are fixed. But right now this is visually
less jarring (otherwise youtube UI will suddenly dim when autoplaying
HDR video).

Bug: 200310158
Test: Verified that plumbing sdr white point is sent to renderengine
Test: librenderengine_test
Test: libcompositionengine_test
Test: DataspaceUtils_test

Change-Id: I5bcea7941935c43e57cd5434e1ec69b41d31f2b4
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 6800004..d503153 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -1057,7 +1057,7 @@
     clientCompositionDisplay.maxLuminance = outputState.displayBrightnessNits > 0.f
             ? outputState.displayBrightnessNits
             : mDisplayColorProfile->getHdrCapabilities().getDesiredMaxLuminance();
-    clientCompositionDisplay.sdrWhitePointNits = outputState.sdrWhitePointNits;
+    clientCompositionDisplay.targetLuminanceNits = outputState.clientTargetWhitePointNits;
 
     // Compute the global color transform matrix.
     if (!outputState.usesDeviceComposition && !getSkipColorTransform()) {
@@ -1217,7 +1217,8 @@
                                        .dataspace = outputDataspace,
                                        .realContentIsVisible = realContentIsVisible,
                                        .clearContent = !clientComposition,
-                                       .blurSetting = blurSetting};
+                                       .blurSetting = blurSetting,
+                                       .whitePointNits = layerState.whitePointNits};
                 results = layerFE.prepareClientCompositionList(targetSettings);
                 if (realContentIsVisible && !results.empty()) {
                     layer->editState().clientCompositionTimestamp = systemTime();