EphemeralTab: Disable contextual search for ephemeral tab

When ephemeral tab and contextual search both rely on overlay panel,
and it's best for only one of them to work at a time. This CL disables
contextual search while ephemeral tab is showing. The other case
is already handled as cs gets dismissed when ephemeral tab is
brought up.

Bug: 864619
Change-Id: I7b0149fd028e8a6940321436ddac9c7901dfd8e8
Reviewed-on: https://chromium-review.googlesource.com/c/1349151
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Reviewed-by: Donn Denman <donnd@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612064}

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java

@@ -354,7 +354,7 @@ public class ContextualSearchManager
     }
 
     /** @return Whether the {@code mSearchPanel} is not {@code null} and is showing. */
-    private boolean isSearchPanelShowing() {
+    boolean isSearchPanelShowing() {
         return mSearchPanel != null && mSearchPanel.isShowing();
     }
 

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchTabHelper.java

@@ -5,11 +5,15 @@
 package org.chromium.chrome.browser.contextualsearch;
 
 import android.app.Activity;
+import android.os.Handler;
 import android.view.ContextMenu;
 
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.browser.compositor.CompositorViewHolder;
 import org.chromium.chrome.browser.compositor.bottombar.OverlayPanel.StateChangeReason;
+import org.chromium.chrome.browser.compositor.bottombar.OverlayPanelManager.OverlayPanelManagerObserver;
+import org.chromium.chrome.browser.compositor.layouts.LayoutManager;
 import org.chromium.chrome.browser.firstrun.FirstRunStatus;
 import org.chromium.chrome.browser.fullscreen.FullscreenOptions;
 import org.chromium.chrome.browser.locale.LocaleManager;
@@ -19,6 +23,8 @@ import org.chromium.chrome.browser.search_engines.TemplateUrlService;
 import org.chromium.chrome.browser.search_engines.TemplateUrlService.TemplateUrlServiceObserver;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.chrome.browser.tab.Tab.TabHidingType;
+import org.chromium.chrome.browser.tabmodel.TabModel.TabSelectionType;
 import org.chromium.content_public.browser.GestureListenerManager;
 import org.chromium.content_public.browser.GestureStateListener;
 import org.chromium.content_public.browser.SelectionPopupController;
@@ -58,6 +64,15 @@ public class ContextualSearchTabHelper
 
     private long mNativeHelper;
 
+    /** {@code true} while observing other overlay panel via {@link OverlayPanelManagerObserver} */
+    private boolean mIsObservingPanel;
+
+    /**
+     * A Tab that has had Contextual Search unhooked from itself because another overlay is
+     * showing on it, or {@code null}.
+     */
+    private Tab mUnhookedTab;
+
     /**
      * Creates a contextual search tab helper for the given tab.
      * @param tab The tab whose contextual search actions will be handled by this helper.
@@ -84,6 +99,74 @@ public class ContextualSearchTabHelper
         mPxToDp = scaleFactor;
     }
 
+    /**
+     * Used to disable contextual search (remove contextual search hooks) when other overlay
+     * panel comes into action.
+     */
+    private OverlayPanelManagerObserver mPanelObserver = new OverlayPanelManagerObserver() {
+        @Override
+        public void onOverlayPanelShown() {
+            // This leaves the handling of the hooks to the responsibility of the activity tab.
+            // Restoring them will be then done by the tab that was the activity tab when
+            // the panel was shown.
+            Tab activityTab = mTab.getActivity().getActivityTabProvider().getActivityTab();
+            if (activityTab != mTab) return;
+
+            // Removes the hooks if the panel other than contextual search panel just got shown.
+            // Post the task on handler since |isSearchPanelShowing| is not reliable right after
+            // this event is invoked because it is based on the panel height which might be
+            // changing for animation effect.
+            new Handler().post(() -> {
+                if (!getContextualSearchManager(mTab).isSearchPanelShowing()) {
+                    mUnhookedTab = activityTab;
+                    updateContextualSearchHooks(mUnhookedTab.getWebContents());
+                }
+            });
+        }
+
+        @Override
+        public void onOverlayPanelHidden() {
+            if (mUnhookedTab != null) {
+                WebContents webContents = mUnhookedTab.getWebContents();
+                mUnhookedTab = null;
+                updateContextualSearchHooks(webContents);
+            }
+        }
+    };
+
+    /**
+     * Starts observing other panel using {@link OverlayPanelManagerObserver} if we're not
+     * already doing it.
+     * @param tab {@link Tab} to get the overlay panel manager to add the observer to.
+     */
+    private void addPanelObserver(Tab tab) {
+        if (mIsObservingPanel || tab.isNativePage()) return;
+        LayoutManager manager = getLayoutManager(tab);
+        if (manager != null) {
+            manager.getOverlayPanelManager().addObserver(mPanelObserver);
+            mIsObservingPanel = true;
+        }
+    }
+
+    /**
+     * Stops observing other panel if we haven't stopped it already.
+     * @param tab {@link Tab} to get the overlay panel manager to remove the observer from.
+     */
+    private void removePanelObserver(Tab tab) {
+        if (!mIsObservingPanel || tab.isNativePage()) return;
+        LayoutManager manager = getLayoutManager(tab);
+        if (manager != null) {
+            manager.getOverlayPanelManager().removeObserver(mPanelObserver);
+            mIsObservingPanel = false;
+        }
+    }
+
+    private static LayoutManager getLayoutManager(Tab tab) {
+        if (tab.getActivity() == null) return null;
+        CompositorViewHolder cvh = tab.getActivity().getCompositorViewHolder();
+        return cvh != null ? cvh.getLayoutManager() : null;
+    }
+
     // ============================================================================================
     // EmptyTabObserver overrides.
     // ============================================================================================
@@ -95,6 +178,23 @@ public class ContextualSearchTabHelper
         if (manager != null) manager.onBasePageLoadStarted();
     }
 
+    @Override
+    public void onPageLoadFinished(Tab tab, String url) {
+        // Makes sure the observer is added. Doing this in |onShown| doesn't cover all
+        // situations as it can be invoked before OverlayPanelManager is ready.
+        addPanelObserver(tab);
+    }
+
+    @Override
+    public void onShown(Tab tab, @TabSelectionType int type) {
+        addPanelObserver(tab);
+    }
+
+    @Override
+    public void onHidden(Tab tab, @TabHidingType int type) {
+        removePanelObserver(tab);
+    }
+
     @Override
     public void onContentChanged(Tab tab) {
         // Native initialization happens after a page loads or content is changed to ensure profile
@@ -131,6 +231,7 @@ public class ContextualSearchTabHelper
         if (NetworkChangeNotifier.isInitialized()) {
             NetworkChangeNotifier.removeConnectionTypeObserver(this);
         }
+        removePanelObserver(tab);
         removeContextualSearchHooks(mWebContents);
         mWebContents = null;
         mContextualSearchManager = null;
@@ -158,8 +259,10 @@ public class ContextualSearchTabHelper
     public void onActivityAttachmentChanged(Tab tab, boolean isAttached) {
         if (isAttached) {
             updateHooksForTab(tab);
+            addPanelObserver(tab);
         } else {
             removeContextualSearchHooks(mWebContents);
+            removePanelObserver(tab);
             mContextualSearchManager = null;
         }
     }
@@ -282,7 +385,7 @@ public class ContextualSearchTabHelper
                 // http://crbug.com/396934).
                 && !manager.isRunningInCompatibilityMode()
                 && !(mTab.isShowingErrorPage() || mTab.isShowingInterstitialPage())
-                && isDeviceOnline(manager);
+                && isDeviceOnline(manager) && mUnhookedTab == null;
     }
 
     /** @return Whether the device is online, or we have disabled online-detection. */