Avoid trying to access UserData on destroyed tabs

This adds a static call for SuspendedTab.isShowing similar to
that of SadTab to make sure we don't call getUserData() on destroyed
tabs.

BUG=973625

Change-Id: Ib16f1991489bdf16129ac568293b0b895bb871ba
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1700478
Commit-Queue: Yusuf Ozuysal <yusufo@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#677123}

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/content/TabContentManager.java

@@ -466,7 +466,7 @@ public class TabContentManager {
     }
 
     private boolean isNativeViewShowing(Tab tab) {
-        return tab != null && (SadTab.isShowing(tab) || SuspendedTab.from(tab).isShowing());
+        return tab != null && (SadTab.isShowing(tab) || SuspendedTab.isShowing(tab));
     }
 
     // Class Object Methods

chrome/android/java/src/org/chromium/chrome/browser/usage_stats/SuspendedTab.java

@@ -38,6 +38,12 @@ public class SuspendedTab extends EmptyTabObserver implements UserData {
     private static final String TAG = "SuspendedTab";
     private static final Class<SuspendedTab> USER_DATA_KEY = SuspendedTab.class;
 
+    public static boolean isShowing(Tab tab) {
+        if (tab == null || !tab.isInitialized()) return false;
+        SuspendedTab suspendedTab = get(tab);
+        return suspendedTab != null && suspendedTab.isShowing();
+    }
+
     public static SuspendedTab from(Tab tab) {
         SuspendedTab suspendedTab = get(tab);
         if (suspendedTab == null) {