[EoC] Guard against null readinessState when canonical url is resolved

Bug: 847119
Change-Id: I5d7210b131304bf09a431d26aaf64ceae0e10a23
Reviewed-on: https://chromium-review.googlesource.com/1077427Reviewed-by: Filip Gorski <fgorski@chromium.org>
Commit-Queue: Patrick Noland <pnoland@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563004}

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

@@ -299,19 +299,28 @@ class FetchHelper {
 
         if (shouldFetchCanonicalUrl(tab)) {
             mFetchRequestedForCurrentTab = true;
+            String url = tab.getUrl();
             tab.getWebContents().getMainFrame().getCanonicalUrlForSharing(new Callback<String>() {
                 @Override
                 public void onResult(String result) {
+                    if (tab != mCurrentTab) {
+                        return;
+                    }
+
                     // Reset mFetchRequestedForCurrentTab so that it remains false if
                     // maybeStartFetchWithCanonicalURLResolved doesn't end up requesting
                     // suggestions. If it does end up requesting suggestions,
-                    // mFetchRequestedForCurrentTab will be set back to true in the same synchronous
-                    // flow of execution, so there shouldn't be a race condition.
+                    // mFetchRequestedForCurrentTab will be set back to true in the same
+                    // synchronous flow of execution, so there shouldn't be a race condition.
                     mFetchRequestedForCurrentTab = false;
+
                     TabFetchReadinessState tabFetchReadinessState = getTabFetchReadinessState(tab);
-                    tabFetchReadinessState.setCanonicalUrl(result);
-                    maybeStartFetchWithCanonicalURLResolved(
-                            tab, getUrlToFetchFor(tab.getUrl(), result));
+                    if (tabFetchReadinessState != null && tabFetchReadinessState.isTrackingPage()
+                            && tabFetchReadinessState.isContextTheSame(url)) {
+                        tabFetchReadinessState.setCanonicalUrl(result);
+                        maybeStartFetchWithCanonicalURLResolved(
+                                tab, getUrlToFetchFor(tab.getUrl(), result));
+                    }
                 }
             });
             return;

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

@@ -418,6 +418,32 @@ public final class FetchHelperTest {
         verify(mDelegate, times(1)).requestSuggestions(DIFFERENT_URL);
     }
 
+    @Test
+    public void canonicalUrl_readinessStateIsNull() {
+        doReturn(true).when(mTab).isLoading();
+
+        FetchHelper helper = createFetchHelper();
+
+        doReturn(mFrameHost).when(mWebContents).getMainFrame();
+        doAnswer(new Answer<Void>() {
+            @Override
+            public Void answer(InvocationOnMock invocation) {
+                if (invocation.getArguments()[0] instanceof Callback) {
+                    closeTab(mTab);
+                    @SuppressWarnings("unchecked")
+                    Callback<String> callback = (Callback<String>) invocation.getArguments()[0];
+                    callback.onResult(DIFFERENT_URL);
+                }
+                return null;
+            }
+        })
+                .when(mFrameHost)
+                .getCanonicalUrlForSharing(any());
+        getTabObserver().onPageLoadFinished(mTab);
+        runUntilFetchPossible();
+        verify(mDelegate, times(0)).requestSuggestions(DIFFERENT_URL);
+    }
+
     private void addTab(Tab tab) {
         getTabModelObserver().didAddTab(tab, TabLaunchType.FROM_LINK);
     }