Add layer updates debugging feature to Skia pipelines

When this property is turned on, we flash green
every time a hardware layer is updated.

Test: Matches the behavior in OpenGLPipeline

BUG:32370375

Change-Id: I916f94eee644c185d8a3f9fa4cd69e087ed1e92d

libs/hwui/pipeline/skia/RenderNodeDrawable.cpp

@@ -164,6 +164,14 @@ void RenderNodeDrawable::drawContent(SkCanvas* canvas) const {
                 paint = &tmpPaint;
             }
             renderNode->getLayerSurface()->draw(canvas, 0, 0, paint);
+
+            if (CC_UNLIKELY(Properties::debugLayersUpdates
+                    && !renderNode->getSkiaLayer()->hasRenderedSinceRepaint)) {
+                renderNode->getSkiaLayer()->hasRenderedSinceRepaint = true;
+                SkPaint layerPaint;
+                layerPaint.setColor(0x7f00ff00);
+                canvas->drawRect(bounds, layerPaint);
+            }
         // composing a software layer with alpha
         } else if (properties.effectiveLayerType() == LayerType::Software) {
             SkPaint paint;

libs/hwui/pipeline/skia/SkiaLayer.h

@@ -30,6 +30,7 @@ struct SkiaLayer
 {
     sk_sp<SkSurface> layerSurface;
     Matrix4 inverseTransformInWindow;
+    bool hasRenderedSinceRepaint = false;
 };
 
 

libs/hwui/pipeline/skia/SkiaPipeline.cpp

@@ -106,6 +106,7 @@ void SkiaPipeline::renderLayersImpl(const LayerUpdateQueue& layers, bool opaque)
                 return;
             }
 
+            layerNode->getSkiaLayer()->hasRenderedSinceRepaint = false;
             layerCanvas->clear(SK_ColorTRANSPARENT);
 
             RenderNodeDrawable root(layerNode, layerCanvas, false);