DevTools: rely on response's "Content-Type" header to refine resource type

Source/devtools/front_end/sdk/Resource.js

Index: Source/devtools/front_end/sdk/Resource.js
diff --git a/Source/devtools/front_end/sdk/Resource.js b/Source/devtools/front_end/sdk/Resource.js
index 00b7909ee96219011095af4a3375d1166848c930..f4b34924c4f596b08e6186044bc248fd77130a2a 100644
--- a/Source/devtools/front_end/sdk/Resource.js
+++ b/Source/devtools/front_end/sdk/Resource.js
@@ -265,6 +265,8 @@ WebInspector.Resource.prototype = {
      */
     contentType: function()
     {
+        if (this.resourceType() === WebInspector.resourceTypes.Document && this.mimeType.indexOf("javascript") !== -1)
+            return WebInspector.resourceTypes.Script;
         return this.resourceType();
     },
 
@@ -289,7 +291,7 @@ WebInspector.Resource.prototype = {
      */
     canonicalMimeType: function()
     {
-        return this.resourceType().canonicalMimeType() || this.mimeType;
+        return this.contentType().canonicalMimeType() || this.mimeType;
     },
 
     /**