Print Preview: Making margin selection sticky (part 1/2).

chrome/browser/resources/print_preview/margin_settings.js

Index: chrome/browser/resources/print_preview/margin_settings.js
diff --git a/chrome/browser/resources/print_preview/margin_settings.js b/chrome/browser/resources/print_preview/margin_settings.js
index a81606cc01136a9242378ab1aaa424482acf698c..1155f95294f25a2ac8ac294011e4fb5c0f3b20e0 100644
--- a/chrome/browser/resources/print_preview/margin_settings.js
+++ b/chrome/browser/resources/print_preview/margin_settings.js
@@ -151,13 +151,19 @@ cr.define('print_preview', function() {
   MarginSettings.POINTS_PER_INCH = 72;
   // Minimum allowed distance in points between top-bottom, left-right margins.
   MarginSettings.MINIMUM_MARGINS_DISTANCE = 36;
-  // Margin list values.
+  // Margin list values. Matches enum MarginType in
+  // printing/print_job_constants.h.
   MarginSettings.MARGINS_VALUE_DEFAULT = 0;
   MarginSettings.MARGINS_VALUE_NO_MARGINS = 1;
-  MarginSettings.MARGINS_VALUE_CUSTOM = 2;
-  MarginSettings.MARGINS_VALUE_MINIMUM = 3;
-  // Default Margins option index.
-  MarginSettings.DEFAULT_MARGINS_OPTION_INDEX = 0;
+  MarginSettings.MARGINS_VALUE_MINIMUM = 2;
+  MarginSettings.MARGINS_VALUE_CUSTOM = 3;
+
+  // Indices in the dropdown correspoding to margins type.
+  MarginSettings.OPTION_INDEX_DEFAULT = 0;
+  MarginSettings.OPTION_INDEX_NO_MARGINS = 1;
+  MarginSettings.OPTION_INDEX_MINIMUM = 2;
+  MarginSettings.OPTION_INDEX_CUSTOM = 3;
+
   // Group name corresponding to the top margin.
   MarginSettings.TOP_GROUP = 'top';
   //  Group name corresponding to the left margin.
@@ -185,6 +191,20 @@ cr.define('print_preview', function() {
     MarginSettings.useMetricSystem = measurementSystem == 0;
   };
 
+  /**
+   * @type {Object} Maps margin type values to indices within the drop-down
+   *     margin list.
+   */
+  MarginSettings.valueToIndex = {};

[kmadhusu, 2011/11/01 17:17:57]

Is there any specific reason to create this object? 
Index and the value are the same all the time. 

MarginSettings.valueToIndex[0] = 0;
MarginSettings.valueToIndex[1] = 1;
MarginSettings.valueToIndex[2] = 2;
MarginSettings.valueToIndex[3] = 3;

[dpapad, 2011/11/01 17:29:14]

It happens to be the same, but this is not a constraint. I did it this way to
allow for reordering the options in the dropdown without any other changes
needed. Otherwise reordering the options will also require to change the "value"
to match the index in 2 places (margin_settings.html and print_job_constants.h).

+  MarginSettings.valueToIndex[MarginSettings.MARGINS_VALUE_DEFAULT] =
+      MarginSettings.OPTION_INDEX_DEFAULT;
+  MarginSettings.valueToIndex[MarginSettings.MARGINS_VALUE_NO_MARGINS] =
+      MarginSettings.OPTION_INDEX_NO_MARGINS;
+  MarginSettings.valueToIndex[MarginSettings.MARGINS_VALUE_MINIMUM] =
+      MarginSettings.OPTION_INDEX_MINIMUM;
+  MarginSettings.valueToIndex[MarginSettings.MARGINS_VALUE_CUSTOM] =
+      MarginSettings.OPTION_INDEX_CUSTOM;
+
   cr.addSingletonGetter(MarginSettings);
 
   MarginSettings.prototype = {
@@ -210,6 +230,13 @@ cr.define('print_preview', function() {
     },
 
     /**
+     * @param {number} The index to be selected within |this.marginList_|.
+     */
+    set selectedMarginsIndex(index) {
+      this.marginList_.selectedIndex = index;
+    },
+
+    /**
      * @return {number} The total width of the plugin in points.
      */
     get totalWidthInPoints() {
@@ -596,7 +623,7 @@ cr.define('print_preview', function() {
     resetMarginsIfNeeded: function() {
       if (this.isCustomMarginsSelected()) {
         this.marginList_.options[
-            MarginSettings.DEFAULT_MARGINS_OPTION_INDEX].selected = true;
+            MarginSettings.OPTION_INDEX_DEFAULT].selected = true;
         this.removeCustomMarginEventListeners_();
         this.forceDisplayingMarginLines_ = true;
         this.lastSelectedOption_ = MarginSettings.MARGINS_VALUE_DEFAULT;