Remove insertUserStyleSheet function and enum UserStyleSheet.

public/web/WebDocument.h

Index: public/web/WebDocument.h
diff --git a/public/web/WebDocument.h b/public/web/WebDocument.h
index 2be43ad575736b2cc1850eaef2109de048927845..9c2db1103fc490175aa92fdf2b97897aaec861d9 100644
--- a/public/web/WebDocument.h
+++ b/public/web/WebDocument.h
@@ -65,11 +65,6 @@ class WebURL;
 // Provides readonly access to some properties of a DOM document.
 class WebDocument : public WebNode {
 public:
-    // FIXME: Stop using this from Chromium code and get rid of this enum.
-    enum UserStyleLevel {
-        UserStyleAuthorLevel
-    };
-
     WebDocument() { }
     WebDocument(const WebDocument& e) : WebNode(e) { }
 
@@ -130,8 +125,6 @@ public:
     // Gets the accessibility object for an object on this page by ID.
     BLINK_EXPORT WebAXObject accessibilityObjectFromID(int axID) const;
     // Inserts the given CSS source code as a stylesheet in the document.
-    // FIXME: Delete insertUserStyleSheet once Chromium code stops calling it.
-    BLINK_EXPORT void insertUserStyleSheet(const WebString& sourceCode, UserStyleLevel);
     BLINK_EXPORT void insertStyleSheet(const WebString& sourceCode);
 
     // Arranges to call WebFrameClient::didMatchCSS(frame(), ...) when one of