[GTS] Tab-to-Grid animation background

This CL sets the Tab-to-Grid animation background color to be the same
as the tab switcher background color.

Change-Id: I7dc736dfa6dcdeda5a0a6f9dc4f49917b2cb9188
Bug: 1013001
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1854167Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Mei Liang <meiliang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706705}

chrome/android/features/start_surface/internal/java/src/org/chromium/chrome/features/start_surface/StartSurfaceLayout.java

@@ -34,6 +34,7 @@ import org.chromium.chrome.browser.compositor.scene_layer.SceneLayer;
 import org.chromium.chrome.browser.compositor.scene_layer.TabListSceneLayer;
 import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager;
 import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.tasks.tab_management.TabSwitcher;
 import org.chromium.chrome.browser.ui.widget.animation.Interpolators;
 import org.chromium.chrome.browser.util.FeatureUtilities;
@@ -136,6 +137,12 @@ public class StartSurfaceLayout extends Layout implements StartSurface.OverviewM
     }
 
     // Layout implementation.
+    @Override
+    public void setTabModelSelector(TabModelSelector modelSelector, TabContentManager manager) {
+        super.setTabModelSelector(modelSelector, manager);
+        mSceneLayer.setTabModelSelector(modelSelector);
+    }
+
     @Override
     public LayoutTab getLayoutTab(int id) {
         return mDummyLayoutTab;

chrome/android/java/src/org/chromium/chrome/browser/compositor/scene_layer/TabListSceneLayer.java

@@ -21,6 +21,7 @@ import org.chromium.chrome.browser.compositor.layouts.content.TabContentManager;
 import org.chromium.chrome.browser.fullscreen.ChromeFullscreenManager;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.util.ColorUtils;
+import org.chromium.chrome.browser.util.FeatureUtilities;
 import org.chromium.ui.resources.ResourceManager;
 
 /**
@@ -145,7 +146,8 @@ public class TabListSceneLayer extends SceneLayer {
     protected int getTabListBackgroundColor(Context context) {
         int colorId = R.color.modern_primary_color;
 
-        if (ChromeFeatureList.isEnabled(ChromeFeatureList.HORIZONTAL_TAB_SWITCHER_ANDROID)) {
+        if (ChromeFeatureList.isEnabled(ChromeFeatureList.HORIZONTAL_TAB_SWITCHER_ANDROID)
+                || FeatureUtilities.isGridTabSwitcherEnabled()) {
             if (mTabModelSelector != null && mTabModelSelector.isIncognitoSelected()) {
                 colorId = R.color.incognito_modern_primary_color;
             } else {