Add traceAsync to TraceUtils

This utility is useful to trace coroutine code, as the beginning and the
end of the event might end up in different threads.

Note that stacks are maintained as long as the same trackName is used.

When no stackName is used, "AsyncTraces" default is used.

Test: New track appearing in a perfetto trace
Bug: 289353932
Change-Id: I0fbf745d058e6a329d6b2229178a52af21e84033

packages/SystemUI/shared/src/com/android/systemui/util/TraceUtils.kt

@@ -18,22 +18,23 @@ package com.android.systemui.util
 
 import android.os.Trace
 import android.os.TraceNameSupplier
+import java.util.concurrent.atomic.AtomicInteger
 
 /**
- * Run a block within a [Trace] section.
- * Calls [Trace.beginSection] before and [Trace.endSection] after the passed block.
+ * Run a block within a [Trace] section. Calls [Trace.beginSection] before and [Trace.endSection]
+ * after the passed block.
  */
 inline fun <T> traceSection(tag: String, block: () -> T): T =
-        if (Trace.isTagEnabled(Trace.TRACE_TAG_APP)) {
-            Trace.traceBegin(Trace.TRACE_TAG_APP, tag)
-            try {
-                block()
-            } finally {
-                Trace.traceEnd(Trace.TRACE_TAG_APP)
-            }
-        } else {
+    if (Trace.isTagEnabled(Trace.TRACE_TAG_APP)) {
+        Trace.traceBegin(Trace.TRACE_TAG_APP, tag)
+        try {
             block()
+        } finally {
+            Trace.traceEnd(Trace.TRACE_TAG_APP)
         }
+    } else {
+        block()
+    }
 
 class TraceUtils {
     companion object {
@@ -43,6 +44,7 @@ class TraceUtils {
 
         /**
          * Helper function for creating a Runnable object that implements TraceNameSupplier.
+         *
          * This is useful for posting Runnables to Handlers with meaningful names.
          */
         inline fun namedRunnable(tag: String, crossinline block: () -> Unit): Runnable {
@@ -51,5 +53,37 @@ class TraceUtils {
                 override fun run() = block()
             }
         }
+
+        /**
+         * Cookie used for async traces. Shouldn't be public, but to use it inside inline methods
+         * there is no other way around.
+         */
+        val lastCookie = AtomicInteger(0)
+
+        /**
+         * Creates an async slice in a track called "AsyncTraces".
+         *
+         * This can be used to trace coroutine code. Note that all usages of this method will appear
+         * under a single track.
+         */
+        inline fun <T> traceAsync(method: String, block: () -> T): T =
+            traceAsync(method, "AsyncTraces", block)
+
+        /**
+         * Creates an async slice in a track with [trackName] while [block] runs.
+         *
+         * This can be used to trace coroutine code. [method] will be the name of the slice,
+         * [trackName] of the track. The track is one of the rows visible in a perfetto trace inside
+         * SystemUI process.
+         */
+        inline fun <T> traceAsync(method: String, trackName: String, block: () -> T): T {
+            val cookie = lastCookie.incrementAndGet()
+            Trace.asyncTraceForTrackBegin(Trace.TRACE_TAG_APP, trackName, method, cookie)
+            try {
+                return block()
+            } finally {
+                Trace.asyncTraceForTrackEnd(Trace.TRACE_TAG_APP, trackName, cookie)
+            }
+        }
     }
 }

packages/SystemUI/src/com/android/systemui/keyguard/domain/interactor/KeyguardQuickAffordanceInteractor.kt

@@ -49,6 +49,7 @@ import com.android.systemui.settings.UserTracker
 import com.android.systemui.shared.customization.data.content.CustomizationProviderContract as Contract
 import com.android.systemui.statusbar.phone.SystemUIDialog
 import com.android.systemui.statusbar.policy.KeyguardStateController
+import com.android.systemui.util.TraceUtils.Companion.traceAsync
 import dagger.Lazy
 import javax.inject.Inject
 import kotlinx.coroutines.CoroutineDispatcher
@@ -442,8 +443,10 @@ constructor(
     }
 
     private suspend fun isFeatureDisabledByDevicePolicy(): Boolean =
-        withContext(backgroundDispatcher) {
-            devicePolicyManager.areKeyguardShortcutsDisabled(userId = userTracker.userId)
+        traceAsync("isFeatureDisabledByDevicePolicy", TAG) {
+            withContext(backgroundDispatcher) {
+                devicePolicyManager.areKeyguardShortcutsDisabled(userId = userTracker.userId)
+            }
         }
 
     companion object {