Fix flake in metrics tests after r779457.

Bug: 1096670
Change-Id: I5780bd39e44b914369047bb054dc191f16a979ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2264792
Auto-Submit: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Steven Holte <holte@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782681}

android_webview/javatests/src/org/chromium/android_webview/test/AwMetricsIntegrationTest.java

@@ -20,7 +20,6 @@ import org.chromium.base.Callback;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.test.util.CommandLineFlags;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.components.metrics.ChromeUserMetricsExtensionProtos.ChromeUserMetricsExtension;
 import org.chromium.components.metrics.MetricsSwitches;
@@ -191,7 +190,6 @@ public class AwMetricsIntegrationTest {
     @Test
     @MediumTest
     @Feature({"AndroidWebView"})
-    @DisabledTest(message = "crbug.com/1096670")
     public void testMetadata_hardwareScreen() throws Throwable {
         ChromeUserMetricsExtension log = mPlatformServiceBridge.waitForNextMetricsLog();
         SystemProfileProto systemProfile = log.getSystemProfile();

components/metrics/metrics_scheduler.cc

@@ -51,6 +51,10 @@ void MetricsScheduler::TaskDone(base::TimeDelta next_interval) {
 }
 
 void MetricsScheduler::TriggerTask() {
+  // This can happen in tests which set a very small timer interval.
+  if (callback_pending_)
+    return;
+
   callback_pending_ = true;
   task_callback_.Run();
 }