Optimize d3.geo.bounds when no projection.

d3.js

@@ -5905,10 +5905,10 @@
   (d3.geo.azimuthalEquidistant = function() {
     return d3_geo_projection(d3_geo_azimuthalEquidistant);
   }).raw = d3_geo_azimuthalEquidistant;
-  d3.geo.bounds = d3_geo_bounds(d3_identity);
+  d3.geo.bounds = d3_geo_bounds();
   function d3_geo_bounds(projection) {
     var x0, y0, x1, y1, bound = {
-      point: boundPoint,
+      point: projection ? boundProjectedPoint : boundPoint,
       lineStart: d3_noop,
       lineEnd: d3_noop,
       polygonStart: function() {
@@ -5918,9 +5918,11 @@
         bound.point = boundPoint;
       }
     };
-    function boundPoint(x, y) {
+    function boundProjectedPoint(x, y) {
       var p = projection([ x, y ]);
-      x = p[0], y = p[1];
+      boundPoint(p[0], p[1]);
+    }
+    function boundPoint(x, y) {
       if (x < x0) x0 = x;
       if (x > x1) x1 = x;
       if (y < y0) y0 = y;

src/geo/bounds.js

@@ -1,8 +1,8 @@
-d3.geo.bounds = d3_geo_bounds(d3_identity);
+d3.geo.bounds = d3_geo_bounds();
 
 function d3_geo_bounds(projection) {
   var x0, y0, x1, y1, bound = {
-    point: boundPoint,
+    point: projection ? boundProjectedPoint : boundPoint,
     lineStart: d3_noop,
     lineEnd: d3_noop,
 
@@ -11,9 +11,12 @@ function d3_geo_bounds(projection) {
     polygonEnd: function() { bound.point = boundPoint; }
   };
 
-  function boundPoint(x, y) {
+  function boundProjectedPoint(x, y) {
     var p = projection([x, y]);
-    x = p[0], y = p[1];
+    boundPoint(p[0], p[1]);
+  }
+
+  function boundPoint(x, y) {
     if (x < x0) x0 = x;
     if (x > x1) x1 = x;
     if (y < y0) y0 = y;