DevTools: Add support for adding source map to a script from the DevTools window.

Source/devtools/front_end/sdk/Script.js

Index: Source/devtools/front_end/sdk/Script.js
diff --git a/Source/devtools/front_end/sdk/Script.js b/Source/devtools/front_end/sdk/Script.js
index de30f4921b2351280d26571b860abdf97c070ae7..a646a7ded254f3dcc49596e80ce00d95ac4950b6 100644
--- a/Source/devtools/front_end/sdk/Script.js
+++ b/Source/devtools/front_end/sdk/Script.js
@@ -58,6 +58,7 @@ WebInspector.Script = function(target, scriptId, sourceURL, startLine, startColu
 
 WebInspector.Script.Events = {
     ScriptEdited: "ScriptEdited",
+    SourceMapURLAdded: "SourceMapURLAdded",
 }
 
 WebInspector.Script.snippetSourceURLPrefix = "snippets:///";
@@ -213,6 +214,17 @@ WebInspector.Script.prototype = {
     },
 
     /**
+     * @param {string} sourceMapURL
+     */
+    addSourceMapURL: function(sourceMapURL)
+    {
+        if (this.sourceMapURL)
+            return;
+        this.sourceMapURL = sourceMapURL;
+        this.dispatchEventToListeners(WebInspector.Script.Events.SourceMapURLAdded, this.sourceMapURL);
+    },
+
+    /**
      * @return {boolean}
      */
     isAnonymousScript: function()