[EoS] Removes unusable context menus from the ExploreSites tile.

The ExploreSites tile is a special one that can't be removed or used
inside an incognito tab.

Bug: 966024
Change-Id: Idf2340ee879575ffe1c0f3402a4d7725326df248
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1635853
Commit-Queue: Justin DeWitt <dewittj@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: Cathy Li <chili@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664535}

chrome/android/java/src/org/chromium/chrome/browser/suggestions/TileGroup.java

@@ -548,11 +548,15 @@ public class TileGroup implements MostVisitedSites.Observer {
         @Override
         public boolean isItemSupported(@ContextMenuItemId int menuItemId) {
             switch (menuItemId) {
-                // Personalized tiles are the only tiles that can be removed.
+                // Personalized tiles are the only tiles that can be removed.  Additionally, the
+                // Explore tile counts as a personalized tile but cannot be removed.
                 case ContextMenuItemId.REMOVE:
-                    return mSuggestion.sectionType == TileSectionType.PERSONALIZED;
+                    return mSuggestion.sectionType == TileSectionType.PERSONALIZED
+                            && mSuggestion.source != TileSource.EXPLORE;
                 case ContextMenuItemId.LEARN_MORE:
                     return SuggestionsConfig.scrollToLoad();
+                case ContextMenuItemId.OPEN_IN_INCOGNITO_TAB:
+                    return mSuggestion.source != TileSource.EXPLORE;
                 default:
                     return true;
             }

chrome/android/javatests/src/org/chromium/chrome/browser/suggestions/TileGroupTest.java

@@ -44,6 +44,8 @@ import org.chromium.content_public.browser.test.util.TestThreadUtils;
 import org.chromium.content_public.browser.test.util.TestTouchUtils;
 import org.chromium.net.test.EmbeddedTestServer;
 
+import java.util.ArrayList;
+import java.util.Date;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeoutException;
 
@@ -81,7 +83,10 @@ public class TileGroupTest {
         mMostVisitedSites.setTileSuggestions(mSiteSuggestionUrls);
 
         mSuggestionsDeps.getFactory().suggestionsSource = new FakeSuggestionsSource();
+        initializeTab();
+    }
 
+    public void initializeTab() throws Exception {
         mActivityTestRule.startMainActivityWithURL(UrlConstants.NTP_URL);
         Tab mTab = mActivityTestRule.getActivity().getActivityTab();
         NewTabPageTestUtils.waitForNtpLoaded(mTab);
@@ -119,6 +124,23 @@ public class TileGroupTest {
         Assert.assertEquals(2, getTileGridLayout().getChildCount());
     }
 
+    @Test
+    @MediumTest
+    @Feature({"NewTabPage"})
+    public void testDismissExploreTileWithContextMenuFails() throws Exception {
+        SiteSuggestion exploreTile = recreateSuggestionsWithExploreTile();
+        initializeTab();
+
+        Assert.assertEquals(4, getTileGridLayout().getChildCount());
+
+        final View tileView = getTileViewFor(exploreTile);
+        TestTouchUtils.performLongClickOnMainSync(
+                InstrumentationRegistry.getInstrumentation(), tileView);
+        Assert.assertFalse(InstrumentationRegistry.getInstrumentation().invokeContextMenuAction(
+                mActivityTestRule.getActivity(), ContextMenuManager.ContextMenuItemId.REMOVE, 0));
+        Assert.assertEquals(4, getTileGridLayout().getChildCount());
+    }
+
     @Test
     @MediumTest
     @Feature({"NewTabPage"})
@@ -239,4 +261,19 @@ public class TileGroupTest {
         callback.waitForCallback("The expected tile was not added.", 0);
         tileContainer.setOnHierarchyChangeListener(null);
     }
+
+    private SiteSuggestion recreateSuggestionsWithExploreTile() {
+        // need a copy of the list in order to modify it.
+        final ArrayList<SiteSuggestion> currentSuggestions =
+                new ArrayList<>(mMostVisitedSites.getCurrentSites());
+
+        SiteSuggestion exploreTile = new SiteSuggestion("chrome-native://explore",
+                "chrome-native://explore", "", TileTitleSource.UNKNOWN, TileSource.EXPLORE,
+                TileSectionType.PERSONALIZED, new Date());
+        currentSuggestions.add(exploreTile);
+        TestThreadUtils.runOnUiThreadBlocking(
+                () -> mMostVisitedSites.setTileSuggestions(currentSuggestions));
+
+        return exploreTile;
+    }
 }