VR: Open NTP when we enter VR with no tabs.

Bug: 740731
Change-Id: I7183ebf13db7a317947c3c0aa5b40080258dd60a
Reviewed-on: https://chromium-review.googlesource.com/899782Reviewed-by: Yash Malik <ymalik@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#534155}

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java

@@ -48,7 +48,6 @@ import org.chromium.chrome.browser.ApplicationLifetime;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
-import org.chromium.chrome.browser.UrlConstants;
 import org.chromium.chrome.browser.customtabs.CustomTabActivity;
 import org.chromium.chrome.browser.help.HelpAndFeedback;
 import org.chromium.chrome.browser.infobar.InfoBarIdentifier;
@@ -1098,17 +1097,6 @@ public class VrShellDelegate
         boolean presenting = mRequestedWebVr || mListeningForWebVrActivate
                 || (justCompletedDon && mListeningForWebVrActivateBeforePause) || mAutopresentWebVr;
         if (!isVrShellEnabled(mVrSupportLevel) && !presenting) return false;
-
-        // TODO(mthiesse): We don't want to show the tab switcher in VR, and there's no easy way to
-        // exit it right now.
-        if (mActivity.isInOverviewMode() && mActivity.getCurrentTabModel().getCount() != 0) {
-            return false;
-        }
-        Tab tab = mActivity.getActivityTab();
-        if (tab != null && tab.isNativePage()
-                && tab.getNativePage().getHost() == UrlConstants.NTP_HOST) {
-            return false;
-        }
         return true;
     }
 

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java

@@ -25,6 +25,7 @@ import org.chromium.base.ThreadUtils;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
+import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.ChromeFeatureList;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
@@ -48,6 +49,7 @@ import org.chromium.chrome.browser.tabmodel.TabModelSelectorObserver;
 import org.chromium.chrome.browser.tabmodel.TabModelSelectorTabObserver;
 import org.chromium.chrome.browser.tabmodel.TabModelUtils;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheet;
+import org.chromium.chrome.browser.widget.newtab.NewTabButton;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content_public.browser.LoadUrlParams;
 import org.chromium.ui.base.WindowAndroid;
@@ -92,6 +94,7 @@ public class VrShellImpl extends GvrLayout implements VrShell, SurfaceHolder.Cal
 
     private InterceptNavigationDelegateImpl mNonVrInterceptNavigationDelegate;
     private TabRedirectHandler mNonVrTabRedirectHandler;
+
     private TabModelSelector mTabModelSelector;
     private float mLastContentWidth;
     private float mLastContentHeight;
@@ -126,6 +129,7 @@ public class VrShellImpl extends GvrLayout implements VrShell, SurfaceHolder.Cal
         mContentVirtualDisplay.setTo(primaryDisplay);
 
         mContentVrWindowAndroid = new VrWindowAndroid(mActivity, mContentVirtualDisplay);
+        reparentAllTabs(mContentVrWindowAndroid);
 
         mCompositorView = mActivity.getCompositorViewHolder().getCompositorView();
         mVrCompositorSurfaceManager = new VrCompositorSurfaceManager(mCompositorView);
@@ -294,8 +298,13 @@ public class VrShellImpl extends GvrLayout implements VrShell, SurfaceHolder.Cal
     @SuppressLint("NewApi")
     public void initializeNative(Tab currentTab, boolean forWebVr,
             boolean webVrAutopresentationExpected, boolean inCct) {
-        // Make sure the bottom sheet (Chrome Home) is hidden.
+        Tab tab = mActivity.getActivityTab();
+        if (mActivity.isInOverviewMode() || tab == null) {
+            launchNTP();
+            tab = mActivity.getActivityTab();
+        }
         if (mActivity.getBottomSheet() != null) {
+            // Make sure the bottom sheet (Chrome Home) is hidden.
             mActivity.getBottomSheet().setSheetState(BottomSheet.SHEET_STATE_PEEK, false);
         }
 
@@ -315,7 +324,6 @@ public class VrShellImpl extends GvrLayout implements VrShell, SurfaceHolder.Cal
                 getGvrApi().getNativeGvrContext(), mReprojectedRendering, displayWidthMeters,
                 displayHeightMeters, dm.widthPixels, dm.heightPixels);
 
-        reparentAllTabs(mContentVrWindowAndroid);
         swapToTab(currentTab);
         createTabList();
         mActivity.getTabModelSelector().addObserver(mTabModelSelectorObserver);
@@ -871,6 +879,11 @@ public class VrShellImpl extends GvrLayout implements VrShell, SurfaceHolder.Cal
                 / mContentVrWindowAndroid.getDisplay().getDipScale();
     }
 
+    private void launchNTP() {
+        NewTabButton button = (NewTabButton) mActivity.findViewById(R.id.new_tab_button);
+        button.callOnClick();
+    }
+
     /**
      * Sets the callback that will be run when VrShellImpl's dispatchTouchEvent
      * is run and the parent consumed the event.

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTransitionTest.java

@@ -43,7 +43,6 @@ import org.chromium.content.browser.test.util.DOMUtils;
 
 import java.lang.ref.WeakReference;
 import java.util.List;
-import java.util.concurrent.Callable;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -291,7 +290,7 @@ public class VrShellTransitionTest {
     }
 
     /**
-     * Tests that you can't enter VR in Overview mode with tabs.
+     * Tests that you can enter VR in Overview mode, and the NTP shows up.
      */
     @Test
     @Restriction(RESTRICTION_TYPE_VIEWER_DAYDREAM)
@@ -307,20 +306,6 @@ public class VrShellTransitionTest {
         });
 
         Assert.assertTrue(activity.isInOverviewMode());
-        Assert.assertFalse(VrTransitionUtils.forceEnterVr());
-
-        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
-            @Override
-            public void run() {
-                activity.getTabModelSelector().closeAllTabs();
-            }
-        });
-        CriteriaHelper.pollUiThread(new Callable<Boolean>() {
-            @Override
-            public Boolean call() throws Exception {
-                return activity.getCurrentTabModel().getCount() == 0;
-            }
-        });
 
         MockVrDaydreamApi mockApi = new MockVrDaydreamApi();
         VrShellDelegateUtils.getDelegateInstance().overrideDaydreamApiForTesting(mockApi);