[DevTools] Remove SDKModels' fromTarget methods

third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleSheetHeader.js

Index: third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleSheetHeader.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleSheetHeader.js b/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleSheetHeader.js
index cc76e5beed0a61ff40b4aeda90e3c6ac4a469ee6..326de94e97466b5e95155ac55c01c37971ac0f0f 100644
--- a/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleSheetHeader.js
+++ b/third_party/WebKit/Source/devtools/front_end/sdk/CSSStyleSheetHeader.js
@@ -48,13 +48,6 @@ SDK.CSSStyleSheetHeader = class {
   }
 
   /**
-   * @return {!SDK.Target}
-   */
-  target() {
-    return this._cssModel.target();
-  }
-
-  /**
    * @return {!SDK.CSSModel}
    */
   cssModel() {
@@ -79,8 +72,7 @@ SDK.CSSStyleSheetHeader = class {
    * @return {string}
    */
   _viaInspectorResourceURL() {
-    var resourceTreeModel = SDK.ResourceTreeModel.fromTarget(this.target());
-    var frame = resourceTreeModel.frameForId(this.frameId);
+    var frame = this._cssModel.target().model(SDK.ResourceTreeModel).frameForId(this.frameId);
     console.assert(frame);
     var parsedURL = new Common.ParsedURL(frame.url);
     var fakeURL = 'inspector://' + parsedURL.host + parsedURL.folderPathComponents;