Fix crashing when closing the very last tab

This CL fixes some closing tab behavior:
 1. Reset strip/grid sheet when closing a group
 2. Update the tab grid sheet title after tab is removed in
    TabGroupModelFilter
 2. Close app when closing the very last tab in Chrome
    when using the TabGroup UI.

Bug: 948527
Change-Id: Ic112475baf6cd718901d0c06019af134573d8cd1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1564883
Commit-Queue: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Yusuf Ozuysal <yusufo@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#650644}

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/tab_management/TabGridSheetCoordinator.java

@@ -12,7 +12,6 @@ import org.chromium.base.ApplicationStatus;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
 import org.chromium.chrome.browser.ThemeColorProvider;
 import org.chromium.chrome.browser.compositor.layouts.content.TabContentManager;
-import org.chromium.chrome.browser.lifecycle.Destroyable;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tabmodel.TabCreatorManager;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
@@ -27,7 +26,7 @@ import java.util.List;
  * {@link TabListCoordinator} as well as the life-cycle of shared component
  * objects.
  */
-public class TabGridSheetCoordinator implements Destroyable {
+public class TabGridSheetCoordinator {
     final static String COMPONENT_NAME = "TabGridSheet";
     private final Context mContext;
     private final TabListCoordinator mTabGridCoordinator;
@@ -56,7 +55,6 @@ public class TabGridSheetCoordinator implements Destroyable {
     /**
      * Destroy any members that needs clean up.
      */
-    @Override
     public void destroy() {
         mTabGridCoordinator.destroy();
         mMediator.destroy();
@@ -95,6 +93,7 @@ public class TabGridSheetCoordinator implements Destroyable {
 
             if (mToolbarCoordinator != null) {
                 mToolbarCoordinator.destroy();
+                mToolbarCoordinator = null;
             }
         }
     }

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/tab_management/TabGridSheetMediator.java

@@ -12,7 +12,6 @@ import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ThemeColorProvider;
 import org.chromium.chrome.browser.UrlConstants;
-import org.chromium.chrome.browser.lifecycle.Destroyable;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tabmodel.EmptyTabModelObserver;
 import org.chromium.chrome.browser.tabmodel.TabCreatorManager;
@@ -35,7 +34,7 @@ import java.util.List;
  * with the components' coordinator as well as managing the state of the bottom
  * sheet.
  */
-class TabGridSheetMediator implements Destroyable {
+class TabGridSheetMediator {
     /**
      * Defines an interface for a {@link TabGridSheetMediator} reset event handler.
      */
@@ -58,6 +57,7 @@ class TabGridSheetMediator implements Destroyable {
     private final ThemeColorProvider mThemeColorProvider;
     private final ThemeColorProvider.ThemeColorObserver mThemeColorObserver;
     private final ThemeColorProvider.TintObserver mTintObserver;
+    private final ResetHandler mResetHandler;
 
     TabGridSheetMediator(Context context, BottomSheetController bottomSheetController,
             ResetHandler resetHandler, PropertyModel model, TabModelSelector tabModelSelector,
@@ -68,6 +68,7 @@ class TabGridSheetMediator implements Destroyable {
         mTabModelSelector = tabModelSelector;
         mTabCreatorManager = tabCreatorManager;
         mThemeColorProvider = themeColorProvider;
+        mResetHandler = resetHandler;
 
         // TODO (ayman): Add instrumentation to observer calls.
         mSheetObserver = new EmptyBottomSheetObserver() {
@@ -83,19 +84,24 @@ class TabGridSheetMediator implements Destroyable {
         // register for tab model
         mTabModelObserver = new EmptyTabModelObserver() {
             @Override
-            public void didCloseTab(int tabId, boolean incognito) {
-                updateBottomSheetTitleAndMargin();
+            public void didAddTab(Tab tab, @TabLaunchType int type) {
+                updateBottomSheet();
             }
 
             @Override
-            public void didAddTab(Tab tab, @TabLaunchType int type) {
-                updateBottomSheetTitleAndMargin();
+            public void tabClosureUndone(Tab tab) {
+                updateBottomSheet();
             }
 
             @Override
             public void didSelectTab(Tab tab, int type, int lastId) {
                 if (type == TabSelectionType.FROM_USER) resetHandler.resetWithListOfTabs(null);
             }
+
+            @Override
+            public void willCloseTab(Tab tab, boolean animate) {
+                updateBottomSheet();
+            }
         };
         mThemeColorObserver =
                 (color, shouldAnimate) -> mModel.set(TabGridSheetProperties.PRIMARY_COLOR, color);
@@ -127,7 +133,6 @@ class TabGridSheetMediator implements Destroyable {
     /**
      * Destroy any members that needs clean up.
      */
-    @Override
     public void destroy() {
         if (mTabModelObserver != null) {
             mTabModelSelector.getTabModelFilterProvider().removeTabModelFilterObserver(
@@ -138,7 +143,7 @@ class TabGridSheetMediator implements Destroyable {
     }
 
     private void showTabGridSheet(TabGridSheetContent sheetContent) {
-        updateBottomSheetTitleAndMargin();
+        updateBottomSheet();
         mBottomSheetController.getBottomSheet().addObserver(mSheetObserver);
         mBottomSheetController.requestShowContent(sheetContent, true);
         mBottomSheetController.expandSheet();
@@ -155,13 +160,18 @@ class TabGridSheetMediator implements Destroyable {
                 : null;
     }
 
-    private void updateBottomSheetTitleAndMargin() {
+    private void updateBottomSheet() {
         Tab currentTab = mTabModelSelector.getCurrentTab();
         if (currentTab == null) return;
         int tabsCount = mTabModelSelector.getTabModelFilterProvider()
                                 .getCurrentTabModelFilter()
                                 .getRelatedTabList(currentTab.getId())
                                 .size();
+        if (tabsCount == 0) {
+            mResetHandler.resetWithListOfTabs(null);
+            return;
+        }
+
         mModel.set(TabGridSheetProperties.HEADER_TITLE,
                 mContext.getResources().getQuantityString(
                         R.plurals.bottom_tab_grid_title_placeholder, tabsCount, tabsCount));

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/tab_management/TabGroupUiMediator.java

@@ -68,7 +68,8 @@ public class TabGroupUiMediator {
     private final ThemeColorProvider.TintObserver mTintObserver;
     private final TabModelSelectorTabObserver mTabModelSelectorTabObserver;
     private final TabModelSelectorObserver mTabModelSelectorObserver;
-    private boolean mIsResetWithNonNullList;
+    private boolean mIsTabGroupUiVisible;
+    private boolean mIsClosingAGroup;
 
     TabGroupUiMediator(
             BottomControlsCoordinator.BottomControlsVisibilityController visibilityController,
@@ -87,12 +88,25 @@ public class TabGroupUiMediator {
         mTabModelObserver = new EmptyTabModelObserver() {
             @Override
             public void didSelectTab(Tab tab, @TabSelectionType int type, int lastId) {
-                if (type == TabSelectionType.FROM_CLOSE
-                        || getRelatedTabsForId(lastId).contains(tab))
-                    return;
+                if (!mIsTabGroupUiVisible) return;
+                if (type == TabSelectionType.FROM_CLOSE && !mIsClosingAGroup) return;
+                if (getRelatedTabsForId(lastId).contains(tab)) return;
                 resetTabStripWithRelatedTabsForId(tab.getId());
             }
 
+            @Override
+            public void willCloseTab(Tab tab, boolean animate) {
+                if (!mIsTabGroupUiVisible) return;
+                Tab currentTab = mTabModelSelector.getCurrentTab();
+                if (currentTab == null) mResetHandler.resetSheetWithListOfTabs(null);
+                int tabsCount = mTabModelSelector.getTabModelFilterProvider()
+                                        .getCurrentTabModelFilter()
+                                        .getRelatedTabList(currentTab.getId())
+                                        .size();
+
+                mIsClosingAGroup = tabsCount == 0;
+            }
+
             @Override
             public void didAddTab(Tab tab, int type) {
                 if (type == TabLaunchType.FROM_CHROME_UI || type == TabLaunchType.FROM_RESTORE)
@@ -128,7 +142,7 @@ public class TabGroupUiMediator {
                                                .getRelatedTabList(tab.getId());
                 int numTabs = listOfTabs.size();
                 // This is set to zero because the UI is hidden.
-                if (!mIsResetWithNonNullList) numTabs = 0;
+                if (!mIsTabGroupUiVisible) numTabs = 0;
                 RecordHistogram.recordCountHistogram("TabStrip.TabCountOnPageLoad", numTabs);
             }
         };
@@ -190,12 +204,12 @@ public class TabGroupUiMediator {
                                        .getRelatedTabList(id);
         if (listOfTabs.size() < 2) {
             mResetHandler.resetStripWithListOfTabs(null);
-            mIsResetWithNonNullList = false;
+            mIsTabGroupUiVisible = false;
         } else {
             mResetHandler.resetStripWithListOfTabs(listOfTabs);
-            mIsResetWithNonNullList = true;
+            mIsTabGroupUiVisible = true;
         }
-        mVisibilityController.setBottomControlsVisible(mIsResetWithNonNullList);
+        mVisibilityController.setBottomControlsVisible(mIsTabGroupUiVisible);
     }
 
     private List<Tab> getRelatedTabsForId(int id) {

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

@@ -615,8 +615,15 @@ public class ChromeTabbedActivity
 
                 private void closeIfNoTabsAndHomepageEnabled(boolean isPendingClosure) {
                     if (getTabModelSelector().getTotalTabCount() == 0) {
-                        // If the last tab is closed, and homepage is enabled, then exit Chrome.
-                        if (HomepageManager.shouldCloseAppWithZeroTabs()) {
+                        // If the last tab is closed, and one of the following is true, then exit
+                        // Chrome:
+                        //   1. If homepage is enabled.
+                        //   2. If TabGroupsAndroid is enabled, and isPendingClosure is true.
+                        //      isPendingClosure is used to avoid calling finish() when closing all
+                        //      tabs in tab switcher.
+                        if (HomepageManager.shouldCloseAppWithZeroTabs()
+                                || (FeatureUtilities.isTabGroupsAndroidEnabled()
+                                        && isPendingClosure)) {
                             finish();
                         } else if (isPendingClosure) {
                             NewTabPageUma.recordNTPImpression(