[ToolbarMVC] Add LocationBarDataObserver

This CL adds an observer interface to LocationBarDataProvider, allowing consumers to listen for changes. It also implements observer registration and notification in LocationBarModel.

Initially, only title change notifications are supported, with the intention to add more fields, e.g. url, in future changes. The corresponding LocationBar "poke" method, setTitleToPageTitle, is removed.

Bug: 1139481
Change-Id: I1240c8152c818a32761a18c846e6d11cf6efa4ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2505800
Commit-Queue: Patrick Noland <pnoland@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Reviewed-by: Brandon Wylie <wylieb@chromium.org>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Reviewed-by: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822842}

chrome/android/java/src/org/chromium/chrome/browser/customtabs/features/toolbar/CustomTabToolbar.java

@@ -58,8 +58,8 @@ import org.chromium.chrome.browser.page_info.ChromePageInfoControllerDelegate;
 import org.chromium.chrome.browser.page_info.ChromePermissionParamsListBuilderDelegate;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TrustedCdn;
+import org.chromium.chrome.browser.toolbar.LocationBarModel;
 import org.chromium.chrome.browser.toolbar.ToolbarColors;
-import org.chromium.chrome.browser.toolbar.ToolbarDataProvider;
 import org.chromium.chrome.browser.toolbar.top.ToolbarActionModeCallback;
 import org.chromium.chrome.browser.toolbar.top.ToolbarLayout;
 import org.chromium.chrome.browser.toolbar.top.ToolbarPhone;
@@ -158,6 +158,7 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
     private String mFirstUrl;
 
     private CustomTabLocationBar mLocationBar;
+    private LocationBarModel mLocationBarModel;
 
     private Runnable mTitleAnimationStarter = new Runnable() {
         @Override
@@ -246,13 +247,15 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
     }
 
     /**
-     *
-     * @param locationBarDataProvider {@link ToolbarDataProvider} to be used for accessing Toolbar
+     * Creates and returns a CustomTab-specific LocationBar. This also retains a reference to the
+     * passed LocationBarModel.
+     * @param locationBarModel {@link LocationBarModel} to be used for accessing LocationBar
      *         state.
      * @return The LocationBar implementation for this CustomTabToolbar.
      */
-    public LocationBar createLocationBar(LocationBarDataProvider locationBarDataProvider) {
-        mLocationBar = new CustomTabLocationBar(locationBarDataProvider);
+    public LocationBar createLocationBar(LocationBarModel locationBarModel) {
+        mLocationBarModel = locationBarModel;
+        mLocationBar = new CustomTabLocationBar(locationBarModel);
         mUrlCoordinator.setDelegate(mLocationBar);
         mLocationBar.updateVisualsForState();
         return mLocationBar;
@@ -358,7 +361,7 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
     @Override
     protected void onNavigatedToDifferentPage() {
         super.onNavigatedToDifferentPage();
-        mLocationBar.setTitleToPageTitle();
+        mLocationBarModel.notifyTitleChanged();
         if (mState == STATE_TITLE_ONLY) {
             if (TextUtils.isEmpty(mFirstUrl)) {
                 mFirstUrl = getToolbarDataProvider().getTab().getUrlString();
@@ -513,7 +516,7 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
     @Override
     protected void onConfigurationChanged(Configuration newConfig) {
         super.onConfigurationChanged(newConfig);
-        mLocationBar.setTitleToPageTitle();
+        mLocationBarModel.notifyTitleChanged();
         mLocationBar.setUrlToPageUrl();
     }
 
@@ -624,11 +627,13 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
     /**
      * Custom tab-specific implementation of the LocationBar interface.
      */
-    private class CustomTabLocationBar implements LocationBar, UrlBar.UrlBarDelegate {
+    private class CustomTabLocationBar
+            implements LocationBar, UrlBar.UrlBarDelegate, LocationBarDataProvider.Observer {
         private LocationBarDataProvider mLocationBarDataProvider;
 
         public CustomTabLocationBar(LocationBarDataProvider locationBarDataProvider) {
             mLocationBarDataProvider = locationBarDataProvider;
+            mLocationBarDataProvider.addObserver(this);
         }
 
         public void onNativeLibraryReady() {
@@ -676,7 +681,7 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
         }
 
         @Override
-        public void setTitleToPageTitle() {
+        public void onTitleChanged() {
             String title = mLocationBarDataProvider.getTitle();
             if (!mLocationBarDataProvider.hasTab() || TextUtils.isEmpty(title)) {
                 mTitleBar.setText("");
@@ -710,7 +715,7 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
             String url = publisherUrl != null ? publisherUrl : tab.getUrlString().trim();
             if (mState == STATE_TITLE_ONLY) {
                 if (!TextUtils.isEmpty(mLocationBarDataProvider.getTitle())) {
-                    setTitleToPageTitle();
+                    onTitleChanged();
                 }
             }
 
@@ -829,7 +834,12 @@ public class CustomTabToolbar extends ToolbarLayout implements View.OnLongClickL
         }
 
         @Override
-        public void destroy() {}
+        public void destroy() {
+            if (mLocationBarDataProvider != null) {
+                mLocationBarDataProvider.removeObserver(this);
+                mLocationBarDataProvider = null;
+            }
+        }
 
         @Override
         public void showUrlBarCursorWithoutFocusAnimations() {}

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

@@ -39,9 +39,6 @@ public interface LocationBar extends Destroyable {
      */
     void setUrlToPageUrl();
 
-    /** Sets the displayed title to the page title. */
-    void setTitleToPageTitle();
-
     /**
      * Sets whether the location bar should have a layout showing a title.
      *

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

@@ -149,11 +149,6 @@ public final class LocationBarCoordinator
         mLocationBarLayout.setUrlToPageUrl();
     }
 
-    @Override
-    public void setTitleToPageTitle() {
-        mLocationBarLayout.setTitleToPageTitle();
-    }
-
     @Override
     public void setShowTitle(boolean showTitle) {
         mLocationBarLayout.setShowTitle(showTitle);

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

@@ -23,6 +23,24 @@ import org.chromium.components.security_state.ConnectionSecurityLevel;
 // TODO(crbug.com/1142887): Refine split between LocationBar properties and sub-component
 // properties, e.g. security state, which is only used by the status icon.
 public interface LocationBarDataProvider {
+    /**
+     * Observer interface for consumers who wish to subscribe to updates of LocationBarData.
+     * Since LocationBarDataProvider data is typically calculated lazily, individual observer
+     * methods don't directly supply the updated value. Instead, the expectation is that the
+     * consumer will query the data it cares about.
+     */
+    interface Observer {
+        void onTitleChanged();
+        // TODO(https://crbug.com/1139481): Add methods for other LocationBarDataProvider
+        // data, e.g. url, NTP, and security state.
+    }
+
+    /** Adds an observer of changes to LocationBarDataProvider's data. */
+    void addObserver(Observer observer);
+
+    /** Removes an observer of changes to LocationBarDataProvider's data. */
+    void removeObserver(Observer observer);
+
     /** Returns The url for the currently active page.*/
     @NonNull
     String getCurrentUrl();

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

@@ -732,8 +732,6 @@ public class LocationBarLayout
         return mStatusCoordinator.getSecurityIconView();
     }
 
-    public void setTitleToPageTitle() {}
-
     public void setShowTitle(boolean showTitle) {}
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/searchwidget/SearchBoxDataProvider.java

@@ -99,6 +99,12 @@ class SearchBoxDataProvider implements LocationBarDataProvider {
         return false;
     }
 
+    @Override
+    public void addObserver(Observer observer) {}
+
+    @Override
+    public void removeObserver(Observer observer) {}
+
     @Override
     public String getCurrentUrl() {
         return SearchWidgetProvider.getDefaultSearchEngineUrl();

chrome/android/java/src/org/chromium/chrome/browser/toolbar/LocationBarModel.java

@@ -16,6 +16,7 @@ import androidx.annotation.Nullable;
 import androidx.annotation.StringRes;
 import androidx.annotation.VisibleForTesting;
 
+import org.chromium.base.ObserverList;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.NativeMethods;
 import org.chromium.chrome.R;
@@ -64,6 +65,8 @@ public class LocationBarModel implements ToolbarDataProvider, LocationBarDataPro
     private boolean mShouldShowOmniboxInOverviewMode;
 
     private long mNativeLocationBarModelAndroid;
+    private ObserverList<LocationBarDataProvider.Observer> mLocationBarDataObservers =
+            new ObserverList<>();
 
     /**
      * Default constructor for this class.
@@ -110,6 +113,7 @@ public class LocationBarModel implements ToolbarDataProvider, LocationBarDataPro
         mTab = tab;
         mIsIncognito = isIncognito;
         updateUsingBrandColor();
+        notifyTitleChanged();
     }
 
     @Override
@@ -125,6 +129,16 @@ public class LocationBarModel implements ToolbarDataProvider, LocationBarDataPro
         return mTab != null && mTab.isInitialized();
     }
 
+    @Override
+    public void addObserver(LocationBarDataProvider.Observer observer) {
+        mLocationBarDataObservers.addObserver(observer);
+    }
+
+    @Override
+    public void removeObserver(LocationBarDataProvider.Observer observer) {
+        mLocationBarDataObservers.removeObserver(observer);
+    }
+
     @Override
     public String getCurrentUrl() {
         // Provide NTP url instead of most recent tab url for searches in overview mode (when Start
@@ -254,6 +268,12 @@ public class LocationBarModel implements ToolbarDataProvider, LocationBarDataPro
         return TextUtils.isEmpty(title) ? title : title.trim();
     }
 
+    public void notifyTitleChanged() {
+        for (LocationBarDataProvider.Observer observer : mLocationBarDataObservers) {
+            observer.onTitleChanged();
+        }
+    }
+
     @Override
     public boolean isIncognito() {
         return mIsIncognito;

chrome/android/java/src/org/chromium/chrome/browser/toolbar/ToolbarManager.java

@@ -454,7 +454,7 @@ public class ToolbarManager implements UrlFocusChangeListener, ThemeColorObserve
 
             @Override
             public void onTitleUpdated(Tab tab) {
-                mLocationBar.setTitleToPageTitle();
+                mLocationBarModel.notifyTitleChanged();
             }
 
             @Override

chrome/android/javatests/src/org/chromium/chrome/browser/omnibox/voice/VoiceRecognitionHandlerTest.java

@@ -210,6 +210,12 @@ public class VoiceRecognitionHandlerTest {
             return false;
         }
 
+        @Override
+        public void addObserver(Observer observer) {}
+
+        @Override
+        public void removeObserver(Observer observer) {}
+
         @Override
         public String getCurrentUrl() {
             return null;

chrome/android/junit/src/org/chromium/chrome/browser/toolbar/LocationBarModelTest.java

@@ -4,6 +4,9 @@
 
 package org.chromium.chrome.browser.toolbar;
 
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import androidx.test.filters.MediumTest;
@@ -19,6 +22,7 @@ import org.mockito.MockitoAnnotations;
 import org.chromium.base.ContextUtils;
 import org.chromium.base.test.BaseRobolectricTestRunner;
 import org.chromium.chrome.browser.customtabs.CustomTabIncognitoManager;
+import org.chromium.chrome.browser.omnibox.LocationBarDataProvider;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.ui.base.WindowAndroid;
@@ -48,6 +52,8 @@ public class LocationBarModelTest {
 
     @Mock
     private Profile mNonPrimaryOTRProfileMock;
+    @Mock
+    private LocationBarDataProvider.Observer mLocationBarDataObserver;
 
     @Before
     public void setUp() {
@@ -125,4 +131,22 @@ public class LocationBarModelTest {
         Profile profile = regularLocationBarModel.getProfile();
         Assert.assertEquals(mRegularProfileMock, profile);
     }
+
+    @Test
+    @MediumTest
+    public void testObserversNotified_titleChange() {
+        LocationBarModel regularLocationBarModel = new TestRegularLocationBarModel(null);
+        regularLocationBarModel.addObserver(mLocationBarDataObserver);
+        verify(mLocationBarDataObserver, never()).onTitleChanged();
+
+        regularLocationBarModel.notifyTitleChanged();
+        verify(mLocationBarDataObserver).onTitleChanged();
+
+        regularLocationBarModel.setTab(mRegularTabMock, false);
+        verify(mLocationBarDataObserver, times(2)).onTitleChanged();
+
+        regularLocationBarModel.removeObserver(mLocationBarDataObserver);
+        regularLocationBarModel.notifyTitleChanged();
+        verify(mLocationBarDataObserver, times(2)).onTitleChanged();
+    }
 }