Reviewed by Pavel Feldman.

        Web Inspector: Eliminate direct dependency of StylesSidebarPane on InspectorBackend
        https://bugs.webkit.org/show_bug.cgi?id=40069

        No new tests are needed, as this is a refactoring.

        * inspector/front-end/CSSStyleModel.js: Added.
        (WebInspector.CSSStyleModel):
        (WebInspector.CSSStyleModel.prototype.getStylesAsync):
        (WebInspector.CSSStyleModel.prototype.getComputedStyleAsync):
        (WebInspector.CSSStyleModel.prototype.setRuleSelector):
        (WebInspector.CSSStyleModel.prototype.addRule):
        (WebInspector.CSSStyleModel.prototype.toggleStyleEnabled):
        (WebInspector.CSSStyleModel.prototype.setCSSText):
        (WebInspector.CSSStyleModel.prototype.applyStyleText):
        * inspector/front-end/StylesSidebarPane.js:
        (WebInspector.StylesSidebarPane.prototype.update.stylesCallback):
        (WebInspector.StylesSidebarPane.prototype.update.computedStyleCallback):
        (WebInspector.StylesSidebarPane.prototype.update):
        (WebInspector.StylesSidebarPane.prototype._arrayContainsInheritedProperty):
        (WebInspector.StylePropertiesSection.prototype.editingSelectorCommitted.successCallback):
        (WebInspector.StylePropertiesSection.prototype.editingSelectorCommitted):
        (WebInspector.BlankStylePropertiesSection.prototype.editingSelectorCommitted.successCallback):
        (WebInspector.BlankStylePropertiesSection.prototype.editingSelectorCommitted):
        (WebInspector.StylePropertyTreeElement.prototype.):
        (WebInspector.StylePropertyTreeElement.prototype):
        * inspector/front-end/inspector.html:
        * inspector/front-end/inspector.js:
        (WebInspector.loaded):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@60680 268f45cc-cd09-0410-ab3c-d52691b4dbfc