https://bugs.webkit.org/show_bug.cgi?id=125244

Reviewed by Joseph Pecoraro.

Profoundly reworked WebInspector.Color to be more efficient and more flexible when
serializing the color to the various supported formats.

* UserInterface/CSSStyleDeclarationTextEditor.js:
(WebInspector.CSSStyleDeclarationTextEditor.prototype._createColorSwatches):
Use new WebInspector.Color.fromString() factory and check for a null return value
rather than an exception to identify invalid color tokens.

* UserInterface/Color.js:
(WebInspector.Color):
Rewrote WebInspector.Color such that it would have, at all times, a canonical
representation in terms of either RGBA or HSLA depending on the format used to
create the color. The new constructor parameters lets the user pass a format
and the RGBA or HSLA components, allowing to bypass the string-only creation
system which was sub-optimal for the new color picker. Additionally, the toString()
method now can provide the most accurate serialization of the color based on the
provided format with a fallback mechanism to RGB/RGBA in cases where the desired
format would incur a loss of fidelity. Finally, simplified the API to only feature
essential features.

(WebInspector.Color.fromString):
New factory method used to create a color from a string.

* UserInterface/ColorPicker.js:
(WebInspector.ColorPicker.prototype.set color):
Keep track of the original color format so that we can use it as the preferred format
when serializing the updated color in _updateColor().

(WebInspector.ColorPicker.prototype._updateColor):
Use the original color format as the prefered formation for color serialization. Also,
use the new WebInspector.Color constructor in lieu of the removed .fromRGBA factory.

(WebInspector.ColorPicker.prototype._updateSliders):
Use the new WebInspector.Color constructor in lieu of the removed .fromRGBA factory.

* UserInterface/ColorWheel.js:
(WebInspector.ColorWheel.prototype._colorAtPointWithBrightness):
Use the new WebInspector.Color constructor in lieu of the removed .fromRGB factory.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@160132 268f45cc-cd09-0410-ab3c-d52691b4dbfc