Bug 1475325 - Hide selection action in some scenarios; r=droeh

Hide the selection action toolbar when the session is unfocused, or when
changing the selection action delegate.

Differential Revision: https://phabricator.services.mozilla.com/D5807

--HG--
extra : moz-landing-system : lando

mobile/android/chrome/geckoview/GeckoViewSelectionActionContent.js

@@ -101,12 +101,14 @@ class GeckoViewSelectionActionContent extends GeckoViewContentModule {
     debug `onEnable`;
     addEventListener("mozcaretstatechanged", this, { mozSystemGroup: true });
     addEventListener("pagehide", this, { capture: true, mozSystemGroup: true });
+    addEventListener("deactivate", this, { mozSystemGroup: true });
   }
 
   onDisable() {
     debug `onDisable`;
     removeEventListener("mozcaretstatechanged", this, { mozSystemGroup: true });
     removeEventListener("pagehide", this, { capture: true, mozSystemGroup: true });
+    removeEventListener("deactivate", this, { mozSystemGroup: true });
   }
 
   /**
@@ -114,8 +116,8 @@ class GeckoViewSelectionActionContent extends GeckoViewContentModule {
    * (mozcaretstatechanged and pagehide) events.
    */
   handleEvent(aEvent) {
-    if (aEvent.type === "pagehide") {
-      // Hide any selection actions on page hide.
+    if (aEvent.type === "pagehide" || aEvent.type === "deactivate") {
+      // Hide any selection actions on page hide or deactivate.
       aEvent = {
         reason: "visibilitychange",
         caretVisibile: false,

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java

@@ -1615,6 +1615,13 @@ public final class GeckoSession extends LayerSession
      * @param delegate SelectionActionDelegate instance or null to unset.
      */
     public void setSelectionActionDelegate(@Nullable SelectionActionDelegate delegate) {
+        if (getSelectionActionDelegate() != null) {
+            // When the delegate is changed or cleared, make sure onHideAction is called
+            // one last time to hide any existing selection action UI. Gecko doesn't keep
+            // track of the old delegate, so we can't rely on Gecko to do that for us.
+            getSelectionActionDelegate().onHideAction(
+                    this, GeckoSession.SelectionActionDelegate.HIDE_REASON_NO_SELECTION);
+        }
         mSelectionActionDelegate.setDelegate(delegate, this);
     }