[Chrome Colors] Properly reset custom color picker.

When opening the color picker second time, it is init by
|customize.customColorPicked| and therefore selecting the same color
doesn't trigger color change event.

Reset |customize.customColorPicked| the same time when rest of the
color picker related values are reset.

Bug: 997120
Change-Id: I494c0a718c0389986de9014603b41754d0299ca5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1769297Reviewed-by: Kristi Park <kristipark@chromium.org>
Commit-Queue: Gayane Petrosyan <gayane@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690055}

chrome/browser/resources/local_ntp/customize.js

@@ -305,11 +305,17 @@ customize.preselectedOptions = {
 customize.colorsMenuLoaded = false;
 
 
+/**
+ * Default color for custom color picker in hex format.
+ * @type {string}
+ */
+customize.defaultCustomColor = '#000000';
+
 /**
  * Custom color picked in hex format.
  * @type {string}
  */
-customize.customColorPicked = '#000000';
+customize.customColorPicked = customize.defaultCustomColor;
 
 /**
  * Sets the visibility of the settings menu and individual options depending on
@@ -2413,6 +2419,7 @@ customize.cancelColor = function() {
  * picker.
  */
 customize.resetColorsMenu = function() {
+  customize.customColorPicked = customize.defaultCustomColor;
   $(customize.IDS.COLOR_PICKER).value = null;
   $(customize.IDS.COLORS_MENU).style.setProperty('--custom-color-border', '');
   $(customize.IDS.COLORS_MENU).style.setProperty('--custom-color-dark', '');