Fix issues that broke editing on browsers without Shadow DOM support.

dart/site/try/src/interaction_manager.dart

Index: dart/site/try/src/interaction_manager.dart
diff --git a/dart/site/try/src/interaction_manager.dart b/dart/site/try/src/interaction_manager.dart
index dba6d5547423d4dea912623aea08ed0853c566a6..bccc995ad88f9b26d7cb3132c250015a8ebecefd 100644
--- a/dart/site/try/src/interaction_manager.dart
+++ b/dart/site/try/src/interaction_manager.dart
@@ -228,6 +228,7 @@ class InteractionContext extends InteractionManager {
   void onKeyUp(KeyboardEvent event) => state.onKeyUp(event);
 
   void onMutation(List<MutationRecord> mutations, MutationObserver observer) {
+    workAroundFirefoxBug();
     try {
       try {
         return state.onMutation(mutations, observer);
@@ -305,7 +306,6 @@ abstract class InteractionState implements InteractionManager {
   void set state(InteractionState newState);
 
   void onStateChanged(InteractionState previous) {
-    print('State change ${previous.runtimeType} -> ${runtimeType}.');
   }
 
   void transitionToInitialState() {
@@ -333,10 +333,8 @@ class InitialState extends InteractionState {
 
   void onKeyUp(KeyboardEvent event) {
     if (computeHasModifier(event)) {
-      print('onKeyUp (modified)');
       onModifiedKeyUp(event);
     } else {
-      print('onKeyUp (unmodified)');
       onUnmodifiedKeyUp(event);
     }
   }
@@ -383,8 +381,6 @@ class InitialState extends InteractionState {
   }
 
   void onMutation(List<MutationRecord> mutations, MutationObserver observer) {
-    print('onMutation');
-
     removeCodeCompletion();
 
     Selection selection = window.getSelection();
@@ -426,7 +422,9 @@ class InitialState extends InteractionState {
 
         node.parent.insertAllBefore(nodes, node);
         node.remove();
-        trySelection.adjust(selection);
+        if (mainEditorPane.contains(trySelection.anchorNode)) {

[ahe, 2014/06/27 11:23:28]

This sometimes happens on Firefox. It is related to when you delete the last
character in a line, but it isn't deterministic.

[Johnni Winther, 2014/07/02 08:40:54]

Put this in a comment.

[ahe, 2014/07/04 13:52:00]

Done.

+          trySelection.adjust(selection);
+        }
 
         // TODO(ahe): We know almost exactly what has changed.  It could be
         // more efficient to only communicate what changed.
@@ -1150,7 +1148,7 @@ void normalizeMutationRecord(MutationRecord record,
   if (!record.removedNodes.isEmpty) {
     normalizedNodes.add(findLine(record.target));
   }
-  if (record.type == "characterData") {
+  if (record.type == "characterData" && record.target.parent != null) {

[ahe, 2014/06/27 11:23:28]

Firefox sends two records when the last character of a text node was deleted.

1. Stating that the text node was removed from its parent element (the text node
is in record.removedNodes, and record.target is the parent).

2. A "characterData" record with the empty text node as target.

[Johnni Winther, 2014/07/02 08:40:54]

Put this in a comment.

[ahe, 2014/07/04 13:52:00]

Done.

     normalizedNodes.add(findLine(record.target));
   }
 }
@@ -1203,3 +1201,17 @@ bool isCompilerStageMarker(String message) {
       message == "Compiling..." ||
       message.startsWith('Compiled ');
 }
+
+void workAroundFirefoxBug() {
+  Selection selection = window.getSelection();
+  if (!isCollapsed(selection)) return;
+  Node node = selection.anchorNode;
+  int offset = selection.anchorOffset;
+  if (selection.anchorNode is Element && selection.anchorOffset != 0) {

[ahe, 2014/06/27 11:23:28]

In some cases, Firefox reports the wrong anchorOffset (always seems to be 6)
when anchorNode is an Element. I've discovered that moving the cursor back and
forth fixes that.

[Johnni Winther, 2014/07/02 08:40:54]

Again, put this in a comment.

[ahe, 2014/07/04 13:52:00]

Done.

+    selection
+        ..modify('move', 'backward', 'character')
+        ..modify('move', 'forward', 'character');
+    print('Worked around Firefox selection bug $node@$offset -> '
+          '${selection.anchorNode}@${selection.anchorOffset}.');
+  }
+}