WebLayer: fix a couple flaky NavigationTests.

Make navigateToStream block until the first contentful paint is
complete. Otherwise, the FCP from that navigation can interfere
with later code that waits for FCP.

Bug: 1144246
Change-Id: Idc16b2ae7c0c9b11fc21e349992b44b671b566d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2511043Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822830}

weblayer/browser/android/javatests/src/org/chromium/weblayer/test/NavigationTest.java

@@ -26,7 +26,6 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.CallbackHelper;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.content_public.browser.test.util.Criteria;
 import org.chromium.content_public.browser.test.util.CriteriaHelper;
 import org.chromium.content_public.browser.test.util.TestThreadUtils;
@@ -926,6 +925,8 @@ public class NavigationTest {
 
     private void navigateToStream(InstrumentationActivity activity, String mimeType,
             String cacheControl) throws Exception {
+        int curOnFirstContentfulPaintCount =
+                mCallback.onFirstContentfulPaintCallback.getCallCount();
         InputStream stream = new ByteArrayInputStream(STREAM_HTML.getBytes(StandardCharsets.UTF_8));
         WebResourceResponse response = new WebResourceResponse(mimeType, "UTF-8", stream);
         if (cacheControl != null) {
@@ -939,10 +940,10 @@ public class NavigationTest {
                 ()
                         -> activity.getTab().getNavigationController().navigate(
                                 Uri.parse(STREAM_URL), params));
+        mCallback.onFirstContentfulPaintCallback.waitForCallback(curOnFirstContentfulPaintCount);
     }
 
-    private void assertStreamContent(int curOnFirstContentfulPaintCount) throws Exception {
-        mCallback.onFirstContentfulPaintCallback.waitForCallback(curOnFirstContentfulPaintCount);
+    private void assertStreamContent() throws Exception {
         assertEquals(STREAM_INNER_BODY,
                 mActivityTestRule.executeScriptAndExtractString("document.body.innerText"));
     }
@@ -956,10 +957,8 @@ public class NavigationTest {
         TestThreadUtils.runOnUiThreadBlocking(() -> { activity.getBrowser().setTopView(null); });
         setNavigationCallback(activity);
 
-        int curOnFirstContentfulPaintCount =
-                mCallback.onFirstContentfulPaintCallback.getCallCount();
         navigateToStream(activity, "text/html", null);
-        assertStreamContent(curOnFirstContentfulPaintCount);
+        assertStreamContent();
     }
 
     @Test
@@ -970,10 +969,8 @@ public class NavigationTest {
         TestThreadUtils.runOnUiThreadBlocking(() -> { activity.getBrowser().setTopView(null); });
         setNavigationCallback(activity);
 
-        int curOnFirstContentfulPaintCount =
-                mCallback.onFirstContentfulPaintCallback.getCallCount();
         navigateToStream(activity, "", null);
-        assertStreamContent(curOnFirstContentfulPaintCount);
+        assertStreamContent();
     }
 
     @Test
@@ -996,7 +993,6 @@ public class NavigationTest {
 
     @Test
     @SmallTest
-    @DisabledTest(message = "https://crbug.com/1144246")
     @MinWebLayerVersion(87)
     public void testWebResponseCached() throws Exception {
         InstrumentationActivity activity = mActivityTestRule.launchShellWithUrl(URL1);
@@ -1011,12 +1007,12 @@ public class NavigationTest {
                 mCallback.onFirstContentfulPaintCallback.getCallCount();
         navigateAndWaitForCompletion(
                 STREAM_URL, () -> { activity.getTab().getNavigationController().goBack(); });
-        assertStreamContent(curOnFirstContentfulPaintCount);
+        mCallback.onFirstContentfulPaintCallback.waitForCallback(curOnFirstContentfulPaintCount);
+        assertStreamContent();
     }
 
     @Test
     @SmallTest
-    @DisabledTest(message = "https://crbug.com/1144246")
     @MinWebLayerVersion(87)
     public void testWebResponseCachedWithSniffedMimeType() throws Exception {
         InstrumentationActivity activity = mActivityTestRule.launchShellWithUrl(URL1);
@@ -1031,7 +1027,8 @@ public class NavigationTest {
                 mCallback.onFirstContentfulPaintCallback.getCallCount();
         navigateAndWaitForCompletion(
                 STREAM_URL, () -> { activity.getTab().getNavigationController().goBack(); });
-        assertStreamContent(curOnFirstContentfulPaintCount);
+        mCallback.onFirstContentfulPaintCallback.waitForCallback(curOnFirstContentfulPaintCount);
+        assertStreamContent();
     }
 
     @Test