Hook into undos in a different way

This way doesn't depend on details of keybindings and
the undo button.

Also, implement this in DrawArea mode.

js/id/graph/history.js

@@ -1,7 +1,7 @@
 iD.History = function() {
     var stack, index,
         imagery_used = 'Bing',
-        dispatch = d3.dispatch('change');
+        dispatch = d3.dispatch('change', 'undone', 'redone');
 
     function perform(actions) {
         actions = Array.prototype.slice.call(actions);
@@ -62,6 +62,7 @@ iD.History = function() {
                 if (stack[index].annotation) break;
             }
 
+            dispatch.undone();
             change(previous);
         },
 
@@ -73,6 +74,7 @@ iD.History = function() {
                 if (stack[index].annotation) break;
             }
 
+            dispatch.redone();
             change(previous);
         },
 

js/id/modes/draw_area.js

@@ -112,16 +112,22 @@ iD.modes.DrawArea = function(wayId) {
 
         d3.select(document)
             .call(keybinding);
+
+        history.on('undone.drawline', function () {
+            controller.enter(iD.modes.Browse());
+        });
     };
 
     mode.exit = function() {
-        var surface = mode.map.surface;
+        var map = mode.map,
+            surface = map.surface,
+            history = mode.history;
 
         surface.selectAll('.way, .node')
             .classed('active', false);
 
-        mode.map.tail(false);
-        mode.map.fastEnable(true);
+        map.tail(false);
+        map.fastEnable(true);
 
         surface
             .on('mousemove.drawarea', null)
@@ -129,6 +135,8 @@ iD.modes.DrawArea = function(wayId) {
 
         keybinding.off();
 
+        history.on('undone.drawline', null);
+
         window.setTimeout(function() {
             mode.map.dblclickEnable(true);
         }, 1000);

js/id/modes/draw_line.js

@@ -126,11 +126,6 @@ iD.modes.DrawLine = function(wayId, direction) {
             controller.enter(iD.modes.Select(way, true));
         }
 
-        function undo() {
-            history.undo();
-            controller.enter(iD.modes.Browse());
-        }
-
         surface
             .on('mousemove.drawline', mousemove)
             .on('click.drawline', click);
@@ -139,26 +134,27 @@ iD.modes.DrawLine = function(wayId, direction) {
             .on('⌫', backspace)
             .on('⌦', del)
             .on('⎋', ret)
-            .on('↩', ret)
-            .on('⌘-Z', undo)
-            .on('⌃-Z', undo);
+            .on('↩', ret);
 
         d3.select(document)
             .call(keybinding);
 
-        d3.select('#undo')
-            .on('click.drawline', undo);
+        history.on('undone.drawline', function () {
+            controller.enter(iD.modes.Browse());
+        });
     };
 
     mode.exit = function() {
-        var surface = mode.map.surface;
+        var map = mode.map,
+            surface = map.surface,
+            history = mode.history;
 
         surface.selectAll('.way, .node')
             .classed('active', false);
 
-        mode.map.tail(false);
-        mode.map.fastEnable(true);
-        mode.map.minzoom(0);
+        map.tail(false);
+        map.fastEnable(true);
+        map.minzoom(0);
 
         surface
             .on('mousemove.drawline', null)
@@ -166,7 +162,7 @@ iD.modes.DrawLine = function(wayId, direction) {
 
         keybinding.off();
 
-        d3.select('#undo').on('click.drawline', null);
+        history.on('undone.drawline', null);
 
         window.setTimeout(function() {
             mode.map.dblclickEnable(true);

test/spec/graph/history.js

@@ -83,6 +83,13 @@ describe("iD.History", function () {
             expect(history.redoAnnotation()).to.equal("annotation");
         });
 
+        it("emits an undone event", function () {
+            history.perform(action);
+            history.on('undone', spy);
+            history.undo();
+            expect(spy).to.have.been.called;
+        });
+
         it("emits a change event", function () {
             history.perform(action);
             history.on('change', spy);
@@ -92,6 +99,14 @@ describe("iD.History", function () {
     });
 
     describe("#redo", function () {
+        it("emits an redone event", function () {
+            history.perform(action);
+            history.undo();
+            history.on('change', spy);
+            history.redo();
+            expect(spy).to.have.been.called;
+        });
+
         it("emits a change event", function () {
             history.perform(action);
             history.undo();