[Instant Start] Show voice search button in search box.

When Instant Start is enabled, the visibility of voice_search_button is
set pre-native. However, TasksSurfaceMediator#initWithNative()
overwrites this value. In this CL, we move setting the default value of
IS_VOICE_RECOGNITION_BUTTON_VISIBLE to the constructor of
TasksSurfaceMediator.

Bug: 1139026
Change-Id: I08fb94576a665975279ace075a6fa6b86874a30f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2523441
Commit-Queue: Xi Han <hanxi@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826493}

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

@@ -720,7 +720,7 @@ public class InstantStartTest {
         ChromeRenderTestRule.sanitize(surface);
         // TODO(crbug.com/1065314): fix favicon.
         mRenderTestRule.render(
-                surface, "singlePane_singleTab_noMV3" + (isFeedV2 ? "_FeedV2" : "_FeedV1"));
+                surface, "singlePane_singleTab_noMV4" + (isFeedV2 ? "_FeedV2" : "_FeedV1"));
 
         // Initializes native.
         startAndWaitNativeInitialization();

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

@@ -1339,6 +1339,47 @@ public class StartSurfaceTest {
         assertEquals(4, cta.getTabModelSelector().getCurrentModel().getCount());
         assertEquals(1, filter.getTabGroupCount());
     }
+
+    @Test
+    @MediumTest
+    @Feature({"StartSurface"})
+    // clang-format off
+    @CommandLineFlags.Add({BASE_PARAMS + "/single/exclude_mv_tiles/true"
+            + "/show_last_active_tab_only/true/show_stack_tab_switcher/true"})
+    public void testShow_SingleAsHomepageV2_VoiceSearchButtonShown() {
+        // clang-format on
+        if (!mImmediateReturn) {
+            onView(withId(org.chromium.chrome.tab_ui.R.id.home_button)).perform(click());
+        }
+
+        CriteriaHelper.pollUiThread(
+                ()
+                        -> mActivityTestRule.getActivity().getLayoutManager() != null
+                        && mActivityTestRule.getActivity().getLayoutManager().overviewVisible());
+
+        onView(withId(R.id.primary_tasks_surface_view)).check(matches(isDisplayed()));
+        onView(withId(R.id.search_box_text)).check(matches(isDisplayed()));
+        onView(withId(R.id.voice_search_button)).check(matches(isDisplayed()));
+    }
+
+    @Test
+    @MediumTest
+    @Feature({"StartSurface"})
+    @CommandLineFlags.Add({BASE_PARAMS + "/single"})
+    public void testShow_SingleAsHomepage_VoiceSearchButtonShown() {
+        if (!mImmediateReturn) {
+            onView(withId(org.chromium.chrome.tab_ui.R.id.home_button)).perform(click());
+        }
+
+        CriteriaHelper.pollUiThread(
+                ()
+                        -> mActivityTestRule.getActivity().getLayoutManager() != null
+                        && mActivityTestRule.getActivity().getLayoutManager().overviewVisible());
+
+        onView(withId(R.id.primary_tasks_surface_view)).check(matches(isDisplayed()));
+        onView(withId(R.id.search_box_text)).check(matches(isDisplayed()));
+        onView(withId(R.id.voice_search_button)).check(matches(isDisplayed()));
+    }
 }
 
 // TODO(crbug.com/1033909): Add more integration tests.

chrome/android/features/tab_ui/java/src/org/chromium/chrome/browser/tasks/TasksSurfaceMediator.java

@@ -60,6 +60,8 @@ class TasksSurfaceMediator implements OverviewModeObserver {
 
         // Set the initial state.
         mModel.set(IS_SURFACE_BODY_VISIBLE, true);
+        mModel.set(IS_FAKE_SEARCH_BOX_VISIBLE, true);
+        mModel.set(IS_VOICE_RECOGNITION_BUTTON_VISIBLE, false);
     }
 
     public void initWithNative(FakeboxDelegate fakeboxDelegate) {
@@ -112,10 +114,6 @@ class TasksSurfaceMediator implements OverviewModeObserver {
         mModel.set(
                 INCOGNITO_COOKIE_CONTROLS_TOGGLE_CHECKED_LISTENER, mIncognitoCookieControlsManager);
         mModel.set(INCOGNITO_COOKIE_CONTROLS_ICON_CLICK_LISTENER, mIncognitoCookieControlsManager);
-
-        // Set the initial state.
-        mModel.set(IS_FAKE_SEARCH_BOX_VISIBLE, true);
-        mModel.set(IS_VOICE_RECOGNITION_BUTTON_VISIBLE, false);
     }
 
     /**