Add UMA metric to track the time elapsed since a WebAPK was last launched

chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java
index 5845ad57a3d9533996df0b4dfee0ab5758dcdade..fd3b21ad5be6cb0dd2c2e095f7f04d288fd8399e 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/webapps/WebappModeTest.java
@@ -24,11 +24,13 @@ import org.chromium.base.ContextUtils;
 import org.chromium.base.test.util.CommandLineFlags;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.RetryOnFailure;
+import org.chromium.base.test.util.ScalableTimeout;
 import org.chromium.base.test.util.UrlUtils;
 import org.chromium.blink_public.platform.WebDisplayMode;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
+import org.chromium.chrome.browser.DeferredStartupHandler;
 import org.chromium.chrome.browser.ShortcutHelper;
 import org.chromium.chrome.browser.ShortcutSource;
 import org.chromium.chrome.browser.tab.Tab;
@@ -267,6 +269,28 @@ public class WebappModeTest {
         });
     }
 
+    /** Test that on first launch {@link WebappDataStorage#hasBeenLaunched()} is set. */
+    @Test
+    @MediumTest
+    @Feature({"Webapps"})
+    public void testSetsHasBeenLaunchedOnFirstLaunch() throws Exception {
+        WebappDataStorage storage = WebappRegistry.getInstance().getWebappDataStorage(WEBAPP_1_ID);
+        Assert.assertFalse(storage.hasBeenLaunched());
+
+        startWebappActivity(WEBAPP_1_ID, WEBAPP_1_URL, WEBAPP_1_TITLE, WEBAPP_ICON);
+
+        // Use a longer timeout because the DeferredStartupHandler is called after the page has
+        // finished loading.
+        CriteriaHelper.pollUiThread(new Criteria("Deferred startup never completed") {
+            @Override
+            public boolean isSatisfied() {
+                return DeferredStartupHandler.getInstance().isDeferredStartupCompleteForApp();
+            }
+        }, ScalableTimeout.scaleTimeout(5000), CriteriaHelper.DEFAULT_POLLING_INTERVAL);
+
+        Assert.assertTrue(storage.hasBeenLaunched());
+    }
+
     /**
      * Starts a WebappActivity for the given data and waits for it to be initialized.  We can't use
      * ActivityUtils.waitForActivity() because of the way WebappActivity is instanced on pre-L