CompoundObserver.getValues retrieve present values, but not update la…

…st reported values.

Note that this adds a test for the above and also tests for discardChanges & setValue.

R=arv
BUG=

Review URL: https://codereview.appspot.com/42990043

src/observe.js

@@ -774,6 +774,16 @@
   CompoundObserver.prototype = createObject({
     __proto__: PathObserver.prototype,
 
+    getValue: function() {
+      var values = [];
+      this.getValues_(values, true);
+      return values;
+    },
+
+    setValue: function() {
+      console.warn('Set to CompoundObserver ignored.');
+    },
+
     // TODO(rafaelw): Consider special-casing when |object| is a PathObserver
     // and path 'value' to avoid explicit observation.
     addPath: function(object, path) {
@@ -821,7 +831,7 @@
       this.depsChanged_.changed = !this.depsChanged_.changed;
     },
 
-    getValues_: function(sync) {
+    getValues_: function(values, sync) {
       if (this.observedSet_)
         this.observedSet_.reset();
 
@@ -834,16 +844,16 @@
             pathOrObserver.getValueFrom(object, this.observedSet_)
 
         if (sync) {
-          this.value_[i / 2] = value;
+          values[i / 2] = value;
           continue;
         }
 
-        if (areSameValue(value, this.value_[i / 2]))
+        if (areSameValue(value, values[i / 2]))
           continue;
 
         oldValues = oldValues || [];
-        oldValues[i / 2] = this.value_[i / 2];
-        this.value_[i / 2] = value;
+        oldValues[i / 2] = values[i / 2];
+        values[i / 2] = value;
       }
 
       if (this.observedSet_)
@@ -853,7 +863,7 @@
     },
 
     check_: function() {
-      var oldValues = this.getValues_();
+      var oldValues = this.getValues_(this.value_);
       if (!oldValues)
         return;
 
@@ -865,7 +875,7 @@
 
     sync_: function(hard) {
       if (hard)
-        this.getValues_(true);
+        this.getValues_(this.value_, true);
     },
 
     close: function() {

tests/test.js

@@ -952,6 +952,26 @@ suite('CompoundObserver Tests', function() {
     assertCompoundPathChanges(['a', 20, 'c'], [-10,, 30],
                               observerCallbackArg);
 
+    model.a = 2;
+    model.b = 3;
+    model.c = 4;
+
+    assert.deepEqual([2, 3, 4], observer.getValue());
+    assertCompoundPathChanges([2, 3, 4], ['a', 20, 'c'],
+                              observerCallbackArg);
+
+    model.a = 'z';
+    model.b = 'y';
+    model.c = 'x';
+    assert.deepEqual(['z', 'y', 'x'], observer.discardChanges());
+    assertNoChanges();
+
+    observer.setValue('blarg!');
+    assert.strictEqual('z', model.a);
+    assert.strictEqual('y', model.b);
+    assert.strictEqual('x', model.c);
+    assertNoChanges();
+
     observer.close();
   });