Adds PowerMetric benchmark to measure Light vs Dark theme

benchmarks/src/main/java/com/google/samples/apps/nowinandroid/foryou/ForYouActions.kt

@@ -88,3 +88,17 @@ fun MacrobenchmarkScope.forYouScrollFeedDownUp() {
     val feedList = device.findObject(By.res("forYou:feed"))
     device.flingElementDownUp(feedList)
 }
+
+fun MacrobenchmarkScope.setAppTheme(isDark: Boolean) {
+    when (isDark) {
+        true -> device.findObject(By.text("Dark")).click()
+        false -> device.findObject(By.text("Light")).click()
+    }
+    device.waitForIdle()
+    device.findObject(By.text("OK")).click()
+
+    // Wait until the top app bar is visible on screen
+    device.wait(Until.hasObject(By.res("niaTopAppBar")), 2_000)
+    val topAppBar = device.findObject(By.res("niaTopAppBar"))
+    topAppBar.wait(Until.hasObject(By.text("Now in Android")), 2_000)
+}

benchmarks/src/main/java/com/google/samples/apps/nowinandroid/interests/ScrollTopicListPowerMetricsBenchmark.kt

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.samples.apps.nowinandroid.interests
+
+import android.os.Build.VERSION_CODES
+import androidx.annotation.RequiresApi
+import androidx.benchmark.macro.CompilationMode
+import androidx.benchmark.macro.ExperimentalMetricApi
+import androidx.benchmark.macro.FrameTimingMetric
+import androidx.benchmark.macro.PowerCategory
+import androidx.benchmark.macro.PowerCategoryDisplayLevel
+import androidx.benchmark.macro.PowerMetric
+import androidx.benchmark.macro.StartupMode
+import androidx.benchmark.macro.junit4.MacrobenchmarkRule
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.uiautomator.By
+import com.google.samples.apps.nowinandroid.PACKAGE_NAME
+import com.google.samples.apps.nowinandroid.allowNotifications
+import com.google.samples.apps.nowinandroid.foryou.forYouScrollFeedDownUp
+import com.google.samples.apps.nowinandroid.foryou.forYouSelectTopics
+import com.google.samples.apps.nowinandroid.foryou.forYouWaitForContent
+import com.google.samples.apps.nowinandroid.foryou.setAppTheme
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@OptIn(ExperimentalMetricApi::class)
+@RequiresApi(VERSION_CODES.Q)
+@RunWith(AndroidJUnit4::class)
+class ScrollTopicListPowerMetricsBenchmark {
+    @get:Rule
+    val benchmarkRule = MacrobenchmarkRule()
+
+    private val categories = PowerCategory.values()
+        .associateWith { PowerCategoryDisplayLevel.TOTAL }
+
+    @Test
+    fun benchmarkStateChangeCompilationLight() =
+        benchmarkStateChangeWithTheme(CompilationMode.Partial(), false)
+
+    @Test
+    fun benchmarkStateChangeCompilationDark() =
+        benchmarkStateChangeWithTheme(CompilationMode.Partial(), true)
+
+    private fun benchmarkStateChangeWithTheme(compilationMode: CompilationMode, isDark: Boolean) =
+        benchmarkRule.measureRepeated(
+            packageName = PACKAGE_NAME,
+            metrics = listOf(FrameTimingMetric(), PowerMetric(PowerMetric.Energy(categories))),
+            compilationMode = compilationMode,
+            iterations = 2,
+            startupMode = StartupMode.WARM,
+            setupBlock = {
+                // Start the app
+                pressHome()
+                startActivityAndWait()
+                allowNotifications()
+                // Navigate to Settings
+                device.findObject(By.desc("Settings")).click()
+                device.waitForIdle()
+                setAppTheme(isDark)
+            },
+        ) {
+            forYouWaitForContent()
+            forYouSelectTopics()
+            repeat(3) {
+                forYouScrollFeedDownUp()
+            }
+        }
+}