DevTools: remove unused parts of the CSS instrumentation.

Source/core/inspector/InspectorInstrumentation.idl

Index: Source/core/inspector/InspectorInstrumentation.idl
diff --git a/Source/core/inspector/InspectorInstrumentation.idl b/Source/core/inspector/InspectorInstrumentation.idl
index 951b44408c5d6959c978e63f72ca83a4b8597a4d..e411fb9a6a1637733e3fdb507f22ecc6e2e47bb0 100644
--- a/Source/core/inspector/InspectorInstrumentation.idl
+++ b/Source/core/inspector/InspectorInstrumentation.idl
@@ -105,18 +105,6 @@ interface InspectorInstrumentation {
     void documentDetached([Keep] Document*);
 
     [CSS, Inline=FastReturn]
-    void willMutateRules(CSSStyleSheet*);
-
-    [CSS, Inline=FastReturn]
-    void didMutateRules([Keep] CSSStyleSheet*);
-
-    [CSS, Inline=FastReturn]
-    void willMutateStyle(CSSStyleDeclaration*);
-
-    [CSS, Inline=FastReturn]
-    void didMutateStyle([Keep] CSSStyleDeclaration*, bool);
-
-    [CSS, Inline=FastReturn]
     void activeStyleSheetsUpdated([Keep] Document*);
 
     [CSS, Inline=FastReturn]