[EoC] Fixing triggering on pages that don't reload

* Adding handling of the onUrlUpdated signal in cases where FetchHelper
  is considers the tab current, but the URL context changed.

Bug: 889518
Change-Id: Ibbf3e57e5861ac0d9fccce7abda946b4dbb6c48a
Reviewed-on: https://chromium-review.googlesource.com/1246592Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594530}

chrome/android/java/src/org/chromium/chrome/browser/contextual_suggestions/FetchHelper.java

@@ -171,6 +171,18 @@ class FetchHelper {
                 getTabFetchReadinessState(tab).updateUrl(url);
             }
 
+            @Override
+            public void onUrlUpdated(Tab tab) {
+                assert !tab.isIncognito();
+                // This address cases, where pages are implemented as a single page app and
+                // switching between articles updates URL, but does not cause a page reload.
+                if (tab == mCurrentTab
+                        && !getTabFetchReadinessState(tab).isContextTheSame(tab.getUrl())) {
+                    clearState();
+                    getTabFetchReadinessState(tab).updateUrl(tab.getUrl());
+                }
+            }
+
             @Override
             public void didFirstVisuallyNonEmptyPaint(Tab tab) {
                 setTimeBaselineAndMaybeFetch(tab);

chrome/android/junit/src/org/chromium/chrome/browser/contextual_suggestions/FetchHelperTest.java

@@ -148,6 +148,27 @@ public final class FetchHelperTest {
         verify(mDelegate, times(2)).clearState();
     }
 
+    @Test
+    public void tabObserver_onUrlUpdated() {
+        FetchHelper helper = createFetchHelper();
+        doReturn(DIFFERENT_URL).when(mTab).getUrl();
+        getTabObserver().onUrlUpdated(mTab);
+        verify(mDelegate, times(1)).clearState();
+        // Normally we would change the suffix here, but ShadowUrlUtilities don't support that now.
+        doReturn(STARTING_URL).when(mTab).getUrl();
+        getTabObserver().onUrlUpdated(mTab);
+        verify(mDelegate, times(2)).clearState();
+
+        // Should be ignored, because URL is the same.
+        getTabObserver().onUrlUpdated(mTab);
+        verify(mDelegate, times(2)).clearState();
+
+        // Should be ignored, because tab is different.
+        doReturn(STARTING_URL).when(mTab2).getUrl();
+        getTabObserver().onUrlUpdated(mTab2);
+        verify(mDelegate, times(2)).clearState();
+    }
+
     @Test
     public void tabObserver_didFirstVisuallyNonEmptyPaint() {
         delayFetchExecutionTest((tabObserver) -> tabObserver.didFirstVisuallyNonEmptyPaint(mTab));