No issue: make StrictMode suppression count thread safe.

app/src/androidTest/java/org/mozilla/fenix/ui/StartupExcessiveResourceUseTest.kt

@@ -73,7 +73,7 @@ class StartupExcessiveResourceUseTest {
         // This might cause intermittents: at an arbitrary point after start up (such as the visual
         // completeness queue), we might run code on the main thread that suppresses StrictMode,
         // causing this number to fluctuate depending on device speed. We'll deal with it if it occurs.
-        val actualSuppresionCount = activityTestRule.activity.components.strictMode.suppressionCount.toInt()
+        val actualSuppresionCount = activityTestRule.activity.components.strictMode.suppressionCount.get().toInt()
         val actualRunBlocking = RunBlockingCounter.count.get()
 
         assertEquals(STRICTMODE_FAILURE_MSG, EXPECTED_SUPPRESSION_COUNT, actualSuppresionCount)

app/src/main/java/org/mozilla/fenix/StrictModeManager.kt

@@ -20,6 +20,7 @@ import mozilla.components.support.ktx.android.os.resetAfter
 import org.mozilla.fenix.components.Components
 import org.mozilla.fenix.perf.Performance
 import org.mozilla.fenix.utils.Mockable
+import java.util.concurrent.atomic.AtomicLong
 
 private const val MANUFACTURE_HUAWEI: String = "HUAWEI"
 private const val MANUFACTURE_ONE_PLUS: String = "OnePlus"
@@ -49,9 +50,11 @@ class StrictModeManager(
      * - a lint check: to ensure this value gets used instead of functions that work around it
      * - code owners: to prevent modifications to these above items without perf knowing
      * to make suppressions a more deliberate act.
+     *
+     * This is an Atomic* so it can be incremented from any thread.
      */
     @VisibleForTesting(otherwise = PRIVATE)
-    var suppressionCount: Long = 0
+    val suppressionCount = AtomicLong(0)
 
     /***
      * Enables strict mode for debug purposes. meant to be run only in the main process.
@@ -120,7 +123,7 @@ class StrictModeManager(
             // This can overflow and crash. However, it's unlikely we'll suppress StrictMode 9
             // quintillion times in a build config where StrictMode is enabled so we don't handle it
             // because it'd increase complexity.
-            suppressionCount += 1
+            val suppressionCount = suppressionCount.incrementAndGet()
 
             // We log so that devs are more likely to notice that we're suppressing StrictMode violations.
             // We add profiler markers so that the perf team can easily identify IO locations in profiles.

app/src/test/java/org/mozilla/fenix/StrictModeManagerTest.kt

@@ -119,8 +119,8 @@ class StrictModeManagerTest {
 
     @Test
     fun `GIVEN we're in debug mode WHEN we suppress StrictMode THEN the suppressed count increases`() {
-        assertEquals(0, debugManager.suppressionCount)
+        assertEquals(0, debugManager.suppressionCount.get())
         debugManager.resetAfter(StrictMode.allowThreadDiskReads()) { "" }
-        assertEquals(1, debugManager.suppressionCount)
+        assertEquals(1, debugManager.suppressionCount.get())
     }
 }