Allow home button when Start surface is on

Before this CL, home button would be hidden when Start surface is on,
except for the single-pane variation.

Bug: 1055561
Change-Id: I8dd7862dffcb42fab77eaf1829ce441d30a5ea34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2112330
Commit-Queue: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756090}

chrome/android/features/start_surface/internal/javatests/src/org/chromium/chrome/features/start_surface/StartSurfaceTest.java

@@ -91,6 +91,8 @@ public class StartSurfaceTest {
     @Feature({"StartSurface"})
     @CommandLineFlags.Add({BASE_PARAMS + "/tasksonly"})
     public void testShowAndHide_TasksOnlySurface() {
+        onView(withId(R.id.home_button)).check(matches(isDisplayed()));
+
         TabUiTestHelper.enterTabSwitcher(mActivityTestRule.getActivity());
 
         onView(withId(R.id.primary_tasks_surface_view)).check(matches(isDisplayed()));
@@ -112,6 +114,8 @@ public class StartSurfaceTest {
             "/hide_switch_when_no_incognito_tabs/true"})
     public void testShowAndHide_OmniboxOnlySurface() {
         // clang-format on
+        onView(withId(R.id.home_button)).check(matches(isDisplayed()));
+
         final ChromeTabbedActivity cta = mActivityTestRule.getActivity();
         TabUiTestHelper.enterTabSwitcher(cta);
 
@@ -147,6 +151,8 @@ public class StartSurfaceTest {
     @Feature({"StartSurface"})
     @CommandLineFlags.Add({BASE_PARAMS + "/twopanes"})
     public void testShowAndHide_TwoPanesSurface() {
+        onView(withId(R.id.home_button)).check(matches(isDisplayed()));
+
         final ChromeTabbedActivity cta = mActivityTestRule.getActivity();
         TabUiTestHelper.enterTabSwitcher(cta);
 
@@ -354,6 +360,8 @@ public class StartSurfaceTest {
     @Feature({"StartSurface"})
     @CommandLineFlags.Add({BASE_PARAMS + "/single"})
     public void testShowAndHide_TabSwitcherInSingleSurface() {
+        onView(withId(R.id.home_button)).check(matches(isDisplayed()));
+
         TabUiTestHelper.enterTabSwitcher(mActivityTestRule.getActivity());
 
         onView(withId(R.id.secondary_tasks_surface_view)).check(matches(isDisplayed()));

chrome/android/java/src/org/chromium/chrome/browser/toolbar/top/ToolbarPhone.java

@@ -74,7 +74,6 @@ import org.chromium.chrome.browser.toolbar.ToolbarColors;
 import org.chromium.chrome.browser.toolbar.bottom.BottomToolbarConfiguration;
 import org.chromium.chrome.browser.toolbar.bottom.BottomToolbarVariationManager;
 import org.chromium.chrome.browser.toolbar.top.TopToolbarCoordinator.UrlExpansionObserver;
-import org.chromium.chrome.features.start_surface.StartSurfaceConfiguration;
 import org.chromium.components.browser_ui.styles.ChromeColors;
 import org.chromium.components.browser_ui.widget.animation.CancelAwareAnimatorListener;
 import org.chromium.components.browser_ui.widget.animation.Interpolators;
@@ -1660,9 +1659,8 @@ public class ToolbarPhone extends ToolbarLayout implements Invalidator.Client, O
         if (mHomeButton == null) return;
 
         boolean hideHomeButton = !mIsHomeButtonEnabled
-                || (mIsBottomToolbarVisible && BottomToolbarVariationManager.isHomeButtonOnBottom())
-                || (StartSurfaceConfiguration.isStartSurfaceEnabled()
-                        && !StartSurfaceConfiguration.isStartSurfaceSinglePaneEnabled());
+                || (mIsBottomToolbarVisible
+                        && BottomToolbarVariationManager.isHomeButtonOnBottom());
         if (hideHomeButton) {
             removeHomeButton();
         } else {