[VR Browsing] Fix bottom margin for NTP in duet

We need to update the bottom margin on browser controls constraint
changes for VR.

Bug: 884803
Change-Id: I684eac23d8aefcaa8ad8c4cddcf12ebc4a6352cc
Reviewed-on: https://chromium-review.googlesource.com/c/1275145Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598797}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/FeedNewTabPage.java

@@ -244,12 +244,9 @@ public class FeedNewTabPage extends NewTabPage {
     @Override
     protected void initializeMainView(Context context) {
         int topPadding = context.getResources().getDimensionPixelOffset(R.dimen.tab_strip_height);
-        int bottomPadding = mTab.getActivity().getFullscreenManager().getBottomControlsHeight();
 
         mRootView = new RootView(context);
-        mRootView.setLayoutParams(new FrameLayout.LayoutParams(
-                FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT));
-        mRootView.setPadding(0, topPadding, 0, bottomPadding);
+        mRootView.setPadding(0, topPadding, 0, 0);
         mUiConfig = new UiConfig(mRootView);
     }
 

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java

@@ -15,6 +15,7 @@ import android.support.v7.widget.RecyclerView;
 import android.text.TextUtils;
 import android.view.LayoutInflater;
 import android.view.View;
+import android.view.ViewGroup;
 
 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.DiscardableReferencePool;
@@ -54,10 +55,12 @@ import org.chromium.chrome.browser.tab.TabObserver;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabSelectionType;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.util.ColorUtils;
+import org.chromium.chrome.browser.util.FeatureUtilities;
 import org.chromium.chrome.browser.util.UrlUtilities;
 import org.chromium.chrome.browser.vr.VrModuleProvider;
 import org.chromium.content_public.browser.NavigationController;
 import org.chromium.content_public.browser.NavigationEntry;
+import org.chromium.content_public.common.BrowserControlsState;
 import org.chromium.net.NetworkChangeNotifier;
 import org.chromium.ui.mojom.WindowOpenDisposition;
 
@@ -312,6 +315,11 @@ public class NewTabPage
             public void onPageLoadStarted(Tab tab, String url) {
                 saveLastScrollPosition();
             }
+
+            @Override
+            public void onBrowserControlsConstraintsUpdated(Tab tab, int constraints) {
+                updateMargins(constraints);
+            }
         };
         mTab.addObserver(mTabObserver);
         updateSearchProviderHasLogo();
@@ -368,6 +376,28 @@ public class NewTabPage
                 index, NAVIGATION_ENTRY_SCROLL_POSITION_KEY, Integer.toString(scrollPosition));
     }
 
+    /** Update the margins for the content when browser controls constraints are changed. */
+    protected void updateMargins(@BrowserControlsState int constraints) {
+        // TODO(mdjones): can this be merged with BasicNativePage's updateMargins?
+
+        View view = getView();
+        ViewGroup.MarginLayoutParams layoutParams =
+                ((ViewGroup.MarginLayoutParams) view.getLayoutParams());
+        if (layoutParams == null) {
+            // We could be updating the margin before the root view is attached to window.
+            layoutParams = new ViewGroup.MarginLayoutParams(
+                    ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
+            view.setLayoutParams(layoutParams);
+        }
+
+        int bottomMargin = 0;
+        if (FeatureUtilities.isBottomToolbarEnabled()
+                && constraints != BrowserControlsState.HIDDEN) {
+            bottomMargin = mTab.getActivity().getFullscreenManager().getBottomControlsHeight();
+        }
+        layoutParams.bottomMargin = bottomMargin;
+    }
+
     /** @return The view container for the new tab page. */
     @VisibleForTesting
     public NewTabPageView getNewTabPageView() {

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPageView.java

@@ -28,7 +28,6 @@ import org.chromium.chrome.browser.suggestions.SuggestionsDependencyFactory;
 import org.chromium.chrome.browser.suggestions.SuggestionsUiDelegate;
 import org.chromium.chrome.browser.suggestions.TileGroup;
 import org.chromium.chrome.browser.tab.Tab;
-import org.chromium.chrome.browser.util.FeatureUtilities;
 import org.chromium.chrome.browser.util.ViewUtils;
 import org.chromium.chrome.browser.widget.displaystyle.UiConfig;
 
@@ -277,11 +276,6 @@ public class NewTabPageView extends FrameLayout {
         // immediately attached to the window if the RecyclerView is scrolled when the NTP
         // is refocused.
         if (mManager.isLocationBarShownInNTP()) mNewTabPageLayout.updateSearchBoxOnScroll();
-
-        if (FeatureUtilities.isBottomToolbarEnabled()) {
-            ((MarginLayoutParams) getLayoutParams()).bottomMargin =
-                    getResources().getDimensionPixelSize(R.dimen.bottom_toolbar_height);
-        }
     }
 
     /**