Add bulk remove options

packages/cassowary/lib/solver.dart

@@ -59,6 +59,13 @@ class Solver {
     return _optimizeObjectiveRow(_objective);
   }
 
+  Result removeConstraints(List<Constraint> constraints) {
+    _SolverBulkUpdate applier = (Constraint c) => removeConstraint(c);
+    _SolverBulkUpdate undoer = (Constraint c) => addConstraint(c);
+
+    return _bulkEdit(constraints, applier, undoer);
+  }
+
   Result removeConstraint(Constraint constraint) {
     _Tag tag = _constraints[constraint];
     if (tag == null) {
@@ -129,6 +136,14 @@ class Solver {
     return Result.success;
   }
 
+  Result removeEditVariables(List<Variable> variables) {
+    _SolverBulkUpdate applier = (Variable v) => removeEditVariable(v);
+    _SolverBulkUpdate undoer = (Variable v) =>
+        addEditVariable(v, _edits[v].constraint.priority);
+
+    return _bulkEdit(variables, applier, undoer);
+  }
+
   Result removeEditVariable(Variable variable) {
     _EditInfo info = _edits[variable];
     if (info == null) {

packages/cassowary/test/cassowary_test.dart

@@ -603,4 +603,25 @@ void main() {
     expect(s.addEditVariables(
          [left.variable, right.variable, mid.variable], 999.0), Result.success);
   });
+
+  test('bulk_remove_constraints_and_variables', () {
+    Solver s = new Solver();
+
+    var left = new Param(0.0);
+    var right = new Param(100.0);
+    var mid = new Param(0.0);
+
+    expect(s.addEditVariables(
+         [left.variable, right.variable, mid.variable], 999.0), Result.success);
+
+    var c1 = left <= mid;
+    var c2 = mid <= right;
+
+    expect(s.addConstraints([c1, c2]), Result.success);
+
+    expect(s.removeConstraints([c1, c2]), Result.success);
+
+    expect(s.removeEditVariables(
+                [left.variable, right.variable, mid.variable]), Result.success);
+  });
 }