Bug 1133155 - Selection Handler closes leaving handles on screen, r=margaret

mobile/android/chrome/content/SelectionHandler.js

@@ -44,6 +44,7 @@ var SelectionHandler = {
   _focusIsRTL: false,
 
   _activeType: 0, // TYPE_NONE
+  _selectionPrivate: null, // private selection reference
   _selectionID: 0, // Unique Selection ID
 
   _draggingHandles: false, // True while user drags text selection handles
@@ -118,9 +119,12 @@ var SelectionHandler = {
     }
 
     switch (aTopic) {
-      // Update handle/caret position on page reflow (keyboard open/close,
-      // dynamic DOM changes, orientation updates, etc).
+      // Update selectionListener and handle/caret positions, on page reflow
+      // (keyboard open/close, dynamic DOM changes, orientation updates, etc).
       case "TextSelection:LayerReflow": {
+        if (this._activeType == this.TYPE_SELECTION) {
+          this._updateSelectionListener();
+        }
         if (this._activeType != this.TYPE_NONE) {
           this._positionHandlesOnChange();
         }
@@ -290,6 +294,41 @@ var SelectionHandler = {
     };
   },
 
+  /**
+   * Add a selection listener to monitor for external selection changes.
+   */
+  _addSelectionListener: function(selection) {
+    this._selectionPrivate = selection.QueryInterface(Ci.nsISelectionPrivate);
+    this._selectionPrivate.addSelectionListener(this);
+  },
+
+  /**
+   * The nsISelection object for an editable can change during DOM mutations,
+   * causing us to stop receiving selectionChange notifications.
+   *
+   * We can detect that after a layer-reflow event, and dynamically update the
+   * listener.
+   */
+  _updateSelectionListener: function() {
+    if (!(this._targetElement instanceof Ci.nsIDOMNSEditableElement)) {
+      return;
+    }
+
+    let selection = this._getSelection();
+    if (this._selectionPrivate != selection.QueryInterface(Ci.nsISelectionPrivate)) {
+      this._removeSelectionListener();
+      this._addSelectionListener(selection);
+    }
+  },
+
+  /**
+   * Remove the selection listener.
+   */
+  _removeSelectionListener: function() {
+    this._selectionPrivate.removeSelectionListener(this);
+    this._selectionPrivate = null;
+  },
+
   /**
    * Observe and react to programmatic SelectionChange notifications.
    */
@@ -359,7 +398,7 @@ var SelectionHandler = {
     }
 
     // Add a listener to end the selection if it's removed programatically
-    selection.QueryInterface(Ci.nsISelectionPrivate).addSelectionListener(this);
+    this._addSelectionListener(selection);
     this._activeType = this.TYPE_SELECTION;
 
     // Figure out the distance between the selection and the click
@@ -1074,7 +1113,7 @@ var SelectionHandler = {
     let selection = this._getSelection();
     if (selection) {
       // Remove our listener before we clear the selection
-      selection.QueryInterface(Ci.nsISelectionPrivate).removeSelectionListener(this);
+      this._removeSelectionListener();
 
       // Remove the selection. For editables, we clear selection without losing
       // element focus. For non-editables, just clear all.