[Omnibox] Fixing NPE when LocationBarLayout gets focus post destroy

In this fix we check for presence of mAutocompleteCoordinator when
running a lambda handling focus change.

We also need to prevent a case of double destroy, which happens in test.

Alternative considered was to have a boolean: mIsDestroyed and check
that where necessary. Choosing a more specific solution as that is more
consistent with the other code we have.

Bug: 1094242
Change-Id: Iba32f931e1ccec76357c551fddd72acddcd1d5df
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2243258Reviewed-by: Patrick Noland <pnoland@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#777941}

chrome/android/java/src/org/chromium/chrome/browser/omnibox/LocationBarLayout.java

@@ -231,9 +231,11 @@ public class LocationBarLayout extends FrameLayout
 
     @Override
     public void destroy() {
-        removeUrlFocusChangeListener(mAutocompleteCoordinator);
-        mAutocompleteCoordinator.destroy();
-        mAutocompleteCoordinator = null;
+        if (mAutocompleteCoordinator != null) {
+            removeUrlFocusChangeListener(mAutocompleteCoordinator);
+            mAutocompleteCoordinator.destroy();
+            mAutocompleteCoordinator = null;
+        }
 
         if (mAssistantVoiceSearchService != null) {
             mAssistantVoiceSearchService.destroy();
@@ -1175,8 +1177,11 @@ public class LocationBarLayout extends FrameLayout
         mStatusViewCoordinator.setUseDarkColors(useDarkColors);
         mStatusViewCoordinator.setIncognitoBadgeVisibility(
                 mToolbarDataProvider.isIncognito() && !mIsTablet);
-        mAutocompleteCoordinator.updateVisualsForState(
-                useDarkColors, mToolbarDataProvider.isIncognito());
+
+        if (mAutocompleteCoordinator != null) {
+            mAutocompleteCoordinator.updateVisualsForState(
+                    useDarkColors, mToolbarDataProvider.isIncognito());
+        }
     }
 
     @Override

chrome/android/javatests/src/org/chromium/chrome/browser/omnibox/LocationBarLayoutTest.java

@@ -611,6 +611,18 @@ public class LocationBarLayoutTest {
                 WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE, softInputModeCallable));
     }
 
+    /** Test NPE when focus callback triggers after LocationBarLayout is destroyed. */
+    @Test
+    @MediumTest
+    @Feature("Omnibox")
+    public void testAutocompleteCoordinatorNpeWhenFocusedAfterDestroy() {
+        LocationBarLayout locationBar = getLocationBar();
+        TestThreadUtils.runOnUiThreadBlocking(() -> {
+            locationBar.destroy();
+            locationBar.onUrlFocusChange(false);
+        });
+    }
+
     /** Load a new URL and also update the locaiton bar models. */
     private Tab loadUrlInNewTabAndUpdateModels(
             String url, boolean incognito, LocationBarLayout locationBar) {