Add TabModel.closeAllTabs(boolean allowDelegation)

BUG=268157

Review URL: https://codereview.chromium.org/657983003

Cr-Commit-Position: refs/heads/master@{#301125}

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/EmptyTabModel.java

@@ -57,6 +57,10 @@ public class EmptyTabModel implements TabModel {
     public void closeAllTabs() {
     }
 
+    @Override
+    public void closeAllTabs(boolean allowDelegation) {
+    }
+
     @Override
     public int getCount() {
         // We must return 0 to be consistent with getTab(i)

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModel.java

@@ -83,6 +83,14 @@ public interface TabModel extends TabList {
      */
     public void closeAllTabs();
 
+    /**
+     * Close all tabs on this model. If allowDelegation is true, the model has the option
+     * of not closing all tabs and delegating the closure to another class.
+     * @param allowDelegation true iff the model may delegate the close all request.
+     *                        false iff the model must close all tabs.
+     */
+    public void closeAllTabs(boolean allowDelegation);
+
     /**
      * @return Whether or not this model supports pending closures.
      */

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabModelBase.java

@@ -323,6 +323,11 @@ public abstract class TabModelBase extends TabModelJniBridge {
 
     @Override
     public void closeAllTabs() {
+        closeAllTabs(true);
+    }
+
+    @Override
+    public void closeAllTabs(boolean allowDelegation) {
         commitAllTabClosures();
 
         while (getCount() > 0) {