Fix TabSuggestionsOrchestratorTest

Fix the mock object, TabModelFilter, in TabSuggestionsOrchestratorTest
to follow the TabModelFilter's contract.

Change-Id: I0c56d55c3cdc7e4b04bd1519b3a37b63d076378c
Bug: 1049917
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2043100
Commit-Queue: Mei Liang <meiliang@chromium.org>
Reviewed-by: David Maunder <davidjm@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#740343}

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

@@ -198,7 +198,7 @@ public class TabContext {
             Tab currentTab = tabModelFilter.getTabAt(i);
             List<Tab> relatedTabs = tabModelFilter.getRelatedTabList(currentTab.getId());
 
-            if (relatedTabs != null && relatedTabs.size() > 1) {
+            if (relatedTabs.size() > 1) {
                 List<Tab> nonClosingTabs = getNonClosingTabs(relatedTabs);
                 existingGroups.add(new TabGroupInfo(
                         ((TabImpl) currentTab).getRootId(), createTabInfoList(nonClosingTabs)));

chrome/android/features/tab_ui/junit/src/org/chromium/chrome/browser/tasks/tab_management/suggestions/TabSuggestionsOrchestratorTest.java

@@ -5,7 +5,6 @@
 package org.chromium.chrome.browser.tasks.tab_management.suggestions;
 
 import static org.mockito.Mockito.any;
-import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.eq;
@@ -91,8 +90,9 @@ public class TabSuggestionsOrchestratorTest {
                 .when(mTabModelFilterProvider)
                 .addTabModelFilterObserver(any(TabModelObserver.class));
         doReturn(mTabModelFilter).when(mTabModelFilterProvider).getCurrentTabModelFilter();
-        // TODO(1049917): According to TabModelFilter, getRelatedTabList returns non-null.
-        doReturn(null).when(mTabModelFilter).getRelatedTabList(anyInt());
+        doReturn(Arrays.asList(sTabs[0])).when(mTabModelFilter).getRelatedTabList(0);
+        doReturn(Arrays.asList(sTabs[1])).when(mTabModelFilter).getRelatedTabList(1);
+        doReturn(Arrays.asList(sTabs[2])).when(mTabModelFilter).getRelatedTabList(2);
         RecordUserAction.setDisabledForTests(true);
         RecordHistogram.setDisabledForTests(true);
     }