Bug 1302936 - Ignore tab clicks when the tab has already been removed. r=sebastian

MozReview-Commit-ID: K0eUnMHI9j1

--HG--
extra : rebase_source : 69ffde7ceb4cddc11116ae63a126c8e023e01195

mobile/android/base/java/org/mozilla/gecko/Tabs.java

@@ -265,7 +265,7 @@ public class Tabs implements GeckoEventListener {
         // This avoids a NPE below, but callers need to be careful to
         // handle this case.
         if (tab == null || oldTab == tab) {
-            return null;
+            return tab;
         }
 
         mSelectedTab = tab;

mobile/android/base/java/org/mozilla/gecko/tabs/TabsGridLayout.java

@@ -102,13 +102,14 @@ class TabsGridLayout extends GridView
         setOnItemClickListener(new OnItemClickListener() {
             @Override
             public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
-                final TabsLayoutItemView tab = (TabsLayoutItemView) view;
-                final int tabId = tab.getTabId();
-                Tabs.getInstance().selectTab(tabId);
+                final TabsLayoutItemView tabView = (TabsLayoutItemView) view;
+                final int tabId = tabView.getTabId();
+                final Tab tab = Tabs.getInstance().selectTab(tabId);
+                if (tab == null) {
+                    return;
+                }
                 autoHidePanel();
-                Tabs.getInstance().notifyListeners(
-                        Tabs.getInstance().getTab(tabId), Tabs.TabEvents.OPENED_FROM_TABS_TRAY
-                );
+                Tabs.getInstance().notifyListeners(tab, Tabs.TabEvents.OPENED_FROM_TABS_TRAY);
             }
         });
 
@@ -577,11 +578,11 @@ class TabsGridLayout extends GridView
                     if (!mSwiping) {
                         final TabsLayoutItemView item = (TabsLayoutItemView) mSwipeView;
                         final int tabId = item.getTabId();
-                        Tabs.getInstance().selectTab(tabId);
+                        final Tab tab = Tabs.getInstance().selectTab(tabId);
+                        if (tab != null) {
                             autoHidePanel();
-                        Tabs.getInstance().notifyListeners(
-                                Tabs.getInstance().getTab(tabId), Tabs.TabEvents.OPENED_FROM_TABS_TRAY
-                        );
+                            Tabs.getInstance().notifyListeners(tab, Tabs.TabEvents.OPENED_FROM_TABS_TRAY);
+                        }
 
                         mVelocityTracker.recycle();
                         mVelocityTracker = null;

mobile/android/base/java/org/mozilla/gecko/tabs/TabsLayout.java

@@ -132,10 +132,15 @@ public abstract class TabsLayout extends RecyclerView
     public void onItemClicked(RecyclerView recyclerView, int position, View v) {
         final TabsLayoutItemView item = (TabsLayoutItemView) v;
         final int tabId = item.getTabId();
-        final Tabs tabs = Tabs.getInstance();
-        tabs.selectTab(tabId);
+        final Tab tab = Tabs.getInstance().selectTab(tabId);
+        if (tab == null) {
+            // The tab that was clicked no longer exists in the tabs list (which can happen if you
+            // tap on a tab while its remove animation is running), so ignore the click.
+            return;
+        }
+
         autoHidePanel();
-        tabs.notifyListeners(tabs.getTab(tabId), Tabs.TabEvents.OPENED_FROM_TABS_TRAY);
+        Tabs.getInstance().notifyListeners(tab, Tabs.TabEvents.OPENED_FROM_TABS_TRAY);
     }
 
     // Updates the selected position in the list so that it will be scrolled to the right place.
@@ -165,9 +170,14 @@ public abstract class TabsLayout extends RecyclerView
     private void closeTab(View view) {
         final TabsLayoutItemView itemView = (TabsLayoutItemView) view;
         final Tab tab = getTabForView(itemView);
+        if (tab == null) {
+            // We can be null here if this is the second closeTab call resulting from a sufficiently
+            // fast double tap on the close tab button.
+            return;
+        }
+
         final boolean closingLastTab = tabsAdapter.getItemCount() == 1;
         Tabs.getInstance().closeTab(tab, true);
-
         if (closingLastTab) {
             autoHidePanel();
         }