Enable ShadeViewDiffer systrace logs

- Enable ShadeViewDiffer "UI Events" systrace logs on debug builds

 - Guard against unnecessary string creation in
   LogBuffer.echoToSystrace() when tracing is disabled

 - Add two new trace sections for debugging ShadeViewDiffer.applySpec()

Test: Capture trace, look for UI Events during applySpec
Bug: 224973321
Change-Id: I438947f43a9fc1bc6ff66e923645fd695cc99543

packages/SystemUI/log/src/com/android/systemui/log/LogBuffer.kt

@@ -271,11 +271,13 @@ constructor(
     }
 
     private fun echoToSystrace(message: LogMessage, strMessage: String) {
-        Trace.instantForTrack(
-            Trace.TRACE_TAG_APP,
-            "UI Events",
-            "$name - ${message.level.shortString} ${message.tag}: $strMessage"
-        )
+        if (Trace.isTagEnabled(Trace.TRACE_TAG_APP)) {
+            Trace.instantForTrack(
+                Trace.TRACE_TAG_APP,
+                "UI Events",
+                "$name - ${message.level.shortString} ${message.tag}: $strMessage"
+            )
+        }
     }
 
     private fun echoToLogcat(message: LogMessage, strMessage: String) {

packages/SystemUI/src/com/android/systemui/log/dagger/LogModule.java

@@ -60,7 +60,7 @@ public class LogModule {
         if (Compile.IS_DEBUG && notifPipelineFlags.isDevLoggingEnabled()) {
             maxSize *= 10;
         }
-        return factory.create("NotifLog", maxSize, false /* systrace */);
+        return factory.create("NotifLog", maxSize, Compile.IS_DEBUG /* systrace */);
     }
 
     /** Provides a logging buffer for all logs related to notifications on the lockscreen. */

packages/SystemUI/src/com/android/systemui/statusbar/notification/collection/render/ShadeViewDiffer.kt

@@ -67,7 +67,10 @@ class ShadeViewDiffer(
     fun getViewLabel(view: View): String =
             nodes.values.firstOrNull { node -> node.view === view }?.label ?: view.toString()
 
-    private fun detachChildren(parentNode: ShadeNode, specMap: Map<NodeController, NodeSpec>) {
+    private fun detachChildren(
+        parentNode: ShadeNode,
+        specMap: Map<NodeController, NodeSpec>
+    ) = traceSection("detachChildren") {
         val views = nodes.values.associateBy { it.view }
         fun detachRecursively(parentNode: ShadeNode, specMap: Map<NodeController, NodeSpec>) {
             val parentSpec = specMap[parentNode.controller]
@@ -124,7 +127,10 @@ class ShadeViewDiffer(
         }
     }
 
-    private fun attachChildren(parentNode: ShadeNode, specMap: Map<NodeController, NodeSpec>) {
+    private fun attachChildren(
+        parentNode: ShadeNode,
+        specMap: Map<NodeController, NodeSpec>
+    ): Unit = traceSection("attachChildren") {
         val parentSpec = checkNotNull(specMap[parentNode.controller])
 
         for ((index, childSpec) in parentSpec.children.withIndex()) {