Remove the unused defaultColor property on ColorSpace instances

This property is not only completely unused now, it never actually appears to have been used. Even though the memory savings, from not initializing these extra typed arrays, won't be significant in the grand scheme of things it still seems completely unnecessary to keep allocating this data.

As far as I can tell, the main reason for the existence of `defaultColor` seem to be for documentation purposes. Hence the code is changed into comments instead, to keep the information around (but without the unnecessary allocations).

src/core/colorspace.js

@@ -53,7 +53,7 @@ var ColorSpace = (function ColorSpaceClosure() {
     }
   }
 
-  // Constructor should define this.numComps, this.defaultColor, this.name
+  // Constructor should define this.numComps, this.name
   function ColorSpace() {
     unreachable('should not call ColorSpace constructor');
   }
@@ -421,15 +421,13 @@ var ColorSpace = (function ColorSpaceClosure() {
  * Separation color space is actually just a DeviceN with one color component.
  * Both color spaces use a tinting function to convert colors to a base color
  * space.
+ *
+ * The default color is `new Float32Array(new Array(numComps).fill(1))`.
  */
 var AlternateCS = (function AlternateCSClosure() {
   function AlternateCS(numComps, base, tintFn) {
     this.name = 'Alternate';
     this.numComps = numComps;
-    this.defaultColor = new Float32Array(numComps);
-    for (var i = 0; i < numComps; ++i) {
-      this.defaultColor[i] = 1;
-    }
     this.base = base;
     this.tintFn = tintFn;
     this.tmpBuf = new Float32Array(base.numComps);
@@ -514,11 +512,13 @@ var PatternCS = (function PatternCSClosure() {
   return PatternCS;
 })();
 
+/**
+ * The default color is `new Uint8Array([0])`.
+ */
 var IndexedCS = (function IndexedCSClosure() {
   function IndexedCS(base, highVal, lookup) {
     this.name = 'Indexed';
     this.numComps = 1;
-    this.defaultColor = new Uint8Array(this.numComps);
     this.base = base;
     this.highVal = highVal;
 
@@ -585,11 +585,13 @@ var IndexedCS = (function IndexedCSClosure() {
   return IndexedCS;
 })();
 
+/**
+ * The default color is `new Float32Array([0])`.
+ */
 var DeviceGrayCS = (function DeviceGrayCSClosure() {
   function DeviceGrayCS() {
     this.name = 'DeviceGray';
     this.numComps = 1;
-    this.defaultColor = new Float32Array(this.numComps);
   }
 
   DeviceGrayCS.prototype = {
@@ -632,11 +634,13 @@ var DeviceGrayCS = (function DeviceGrayCSClosure() {
   return DeviceGrayCS;
 })();
 
+/**
+ * The default color is `new Float32Array([0, 0, 0])`.
+ */
 var DeviceRgbCS = (function DeviceRgbCSClosure() {
   function DeviceRgbCS() {
     this.name = 'DeviceRGB';
     this.numComps = 3;
-    this.defaultColor = new Float32Array(this.numComps);
   }
   DeviceRgbCS.prototype = {
     getRgb: ColorSpace.prototype.getRgb,
@@ -684,6 +688,9 @@ var DeviceRgbCS = (function DeviceRgbCSClosure() {
   return DeviceRgbCS;
 })();
 
+/**
+ * The default color is `new Float32Array([0, 0, 0, 1])`.
+ */
 var DeviceCmykCS = (function DeviceCmykCSClosure() {
   // The coefficients below was found using numerical analysis: the method of
   // steepest descent for the sum((f_i - color_value_i)^2) for r/g/b colors,
@@ -730,9 +737,6 @@ var DeviceCmykCS = (function DeviceCmykCSClosure() {
   function DeviceCmykCS() {
     this.name = 'DeviceCMYK';
     this.numComps = 4;
-    this.defaultColor = new Float32Array(this.numComps);
-    // Set the fourth component to the maximum value for a black color.
-    this.defaultColor[3] = 1;
   }
   DeviceCmykCS.prototype = {
     getRgb: ColorSpace.prototype.getRgb,
@@ -771,14 +775,15 @@ var DeviceCmykCS = (function DeviceCmykCSClosure() {
   return DeviceCmykCS;
 })();
 
-//
+/**
-// CalGrayCS: Based on "PDF Reference, Sixth Ed", p.245
+ * CalGrayCS: Based on "PDF Reference, Sixth Ed", p.245
-//
+ *
+ * The default color is `new Float32Array([0])`.
+ */
 var CalGrayCS = (function CalGrayCSClosure() {
   function CalGrayCS(whitePoint, blackPoint, gamma) {
     this.name = 'CalGray';
     this.numComps = 1;
-    this.defaultColor = new Float32Array(this.numComps);
 
     if (!whitePoint) {
       throw new FormatError(
@@ -875,9 +880,11 @@ var CalGrayCS = (function CalGrayCSClosure() {
   return CalGrayCS;
 })();
 
-//
+/**
-// CalRGBCS: Based on "PDF Reference, Sixth Ed", p.247
+ * CalRGBCS: Based on "PDF Reference, Sixth Ed", p.247
-//
+ *
+ * The default color is `new Float32Array([0, 0, 0])`.
+ */
 var CalRGBCS = (function CalRGBCSClosure() {
   // See http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html for these
   // matrices.
@@ -908,7 +915,6 @@ var CalRGBCS = (function CalRGBCSClosure() {
   function CalRGBCS(whitePoint, blackPoint, gamma, matrix) {
     this.name = 'CalRGB';
     this.numComps = 3;
-    this.defaultColor = new Float32Array(this.numComps);
 
     if (!whitePoint) {
       throw new FormatError(
@@ -1162,14 +1168,15 @@ var CalRGBCS = (function CalRGBCSClosure() {
   return CalRGBCS;
 })();
 
-//
+/**
-// LabCS: Based on "PDF Reference, Sixth Ed", p.250
+ * LabCS: Based on "PDF Reference, Sixth Ed", p.250
-//
+ *
+ * The default color is `new Float32Array([0, 0, 0])`.
+ */
 var LabCS = (function LabCSClosure() {
   function LabCS(whitePoint, blackPoint, range) {
     this.name = 'Lab';
     this.numComps = 3;
-    this.defaultColor = new Float32Array(this.numComps);
 
     if (!whitePoint) {
       throw new FormatError(