Bug 1343037 part 17. Remove the now-unused nsITextControlElement::GetSelectionRange. r=ehsan

This makes GetSelectionRange non-virtual on HTMLInputElement and HTMLTextareaElement.

MozReview-Commit-ID: HhmTHjw8AwW

dom/html/HTMLInputElement.h

@@ -240,9 +240,6 @@ public:
   NS_IMETHOD_(void) InitializeKeyboardEventListeners() override;
   NS_IMETHOD_(void) OnValueChanged(bool aNotify, bool aWasInteractiveUserChange) override;
   NS_IMETHOD_(bool) HasCachedSelection() override;
-  virtual void GetSelectionRange(int32_t* aSelectionStart,
-                                 int32_t* aSelectionEnd,
-                                 ErrorResult& aRv) override;
 
   // Methods for nsFormFillController so it can do selection operations on input
   // types the HTML spec doesn't support them on, like "email".
@@ -1489,6 +1486,14 @@ protected:
    */
   void UpdateApzAwareFlag();
 
+  /**
+   * A helper to get the current selection range.  Will throw on the ErrorResult
+   * if we have no editor state.
+   */
+  void GetSelectionRange(int32_t* aSelectionStart,
+                         int32_t* aSelectionEnd,
+                         ErrorResult& aRv);
+
   nsCOMPtr<nsIControllers> mControllers;
 
   /*