Add plumbing for HDR WebView

Bug: 279030860
Test: make
Change-Id: Idc7879193c6190a3fadfb46d67fe81eb47101283

libs/hwui/effects/GainmapRenderer.cpp

diff --git a/libs/hwui/effects/GainmapRenderer.cpp b/libs/hwui/effects/GainmapRenderer.cpp
index bfe4eaf..613f52b 100644
--- a/libs/hwui/effects/GainmapRenderer.cpp
+++ b/libs/hwui/effects/GainmapRenderer.cpp
@@ -38,7 +38,7 @@
 
 using namespace renderthread;
 
-static float getTargetHdrSdrRatio(const SkColorSpace* destColorspace) {
+float getTargetHdrSdrRatio(const SkColorSpace* destColorspace) {
     // We should always have a known destination colorspace. If we don't we must be in some
     // legacy mode where we're lost and also definitely not going to HDR
     if (destColorspace == nullptr) {