[Media Intent Handler] Fix broken watchtime metric

This CL re-adds logic to log MediaLauncherActivity in the
WebappCustomTabTimeSpentLogger. This was accidentally removed in a
rebase.

Bug: 935777
Change-Id: Ifa553184ab3e598cd3c0787eead8845a3b4c0695
Reviewed-on: https://chromium-review.googlesource.com/c/1493441
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: Tommy Steimel <steimel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636483}
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappCustomTabTimeSpentLogger.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappCustomTabTimeSpentLogger.java
index aba94f3..d096a51 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappCustomTabTimeSpentLogger.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappCustomTabTimeSpentLogger.java
@@ -48,6 +48,9 @@
             case LaunchSourceType.WEBAPK:
                 umaSuffix = ".WebApk";
                 break;
+            case LaunchSourceType.MEDIA_LAUNCHER_ACTIVITY:
+                umaSuffix = ".MediaLauncherActivity";
+                break;
             default:
                 umaSuffix = ".Other";
                 break;