Fix ReturnToChromeTest#testInitialScrollIndex

The test tests tab grid view containing screenshots of web pages.
Previously the web pages were scrollable and the sreenshorts might
contain scrollbars, but the existence and opacity of the scrollbars
depended on timing.

Let the test use a shorter web page which is not scrollable to avoid
the flakiness.

See
https://storage.cloud.google.com/chromium-result-details/7633a0d7f0a2344a68bfd8c195ffd34615863c8a
for the change of the golden file.

Bug: 1032754
Change-Id: If47d333560d2070574b25a05d0cc39e44d97508b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1961290
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#724491}

chrome/android/javatests/src/org/chromium/chrome/browser/tasks/ReturnToChromeTest.java

@@ -21,6 +21,7 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.test.util.CommandLineFlags;
+import org.chromium.base.test.util.DisableIf;
 import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.Restriction;
@@ -63,7 +64,7 @@ public class ReturnToChromeTest {
 
         EmbeddedTestServer testServer =
                 EmbeddedTestServer.createAndStartServer(InstrumentationRegistry.getContext());
-        mUrl = testServer.getURL("/chrome/test/data/android/navigate/simple.html");
+        mUrl = testServer.getURL("/chrome/test/data/android/about.html");
 
         mActivityTestRule.startMainActivityOnBlankPage();
     }
@@ -260,8 +261,7 @@ public class ReturnToChromeTest {
     // clang-format off
     @CommandLineFlags.Add({BASE_PARAMS + "/" + TAB_SWITCHER_ON_RETURN_MS + "/0"})
     @Restriction(UiRestriction.RESTRICTION_TYPE_PHONE)
-    @DisabledTest(message = "https://crbug.com/1032754")  // temporary
-    // @DisableIf.Build(hardware_is = "bullhead", message = "https://crbug.com/1025241")
+    @DisableIf.Build(hardware_is = "bullhead", message = "https://crbug.com/1025241")
     public void testInitialScrollIndex() throws Exception {
         // clang-format on
         TabUiTestHelper.prepareTabsWithThumbnail(mActivityTestRule, 10, 0, mUrl);

chrome/test/data/android/render_tests/ReturnToChromeTest.10_web_tabs-select_last.Nexus_5-19.png.sha1

-0100e2b42e507091905f7d6bb03b74fa635002be
+93a32a7c0dd79074f2d1d40038f0e46b122de0ba
\ No newline at end of file