Bug 1352968 part 6 - Remove unused Servo_ImportRule_GetSheet. r=heycam

This function was initially added in bug 1304792, but its only usage was
later removed in bug 1352763.

The name conflicts with another function (which basically does the same
thing without refcount manipulation) I'm adding in a later patch, so I
have to remove it first.

MozReview-Commit-ID: 6fO4EDJUg7R

--HG--
extra : source : 3f7f683b64f42d22a09138cfe01d8ca42d435aa3

layout/style/ServoBindingList.h

@@ -33,9 +33,6 @@ SERVO_BINDING_FUNC(Servo_StyleSheet_FromUTF8Bytes, RawServoStyleSheetStrong,
                    RawGeckoURLExtraData* extra_data,
                    uint32_t line_number_offset,
                    nsCompatibility quirks_mode)
-SERVO_BINDING_FUNC(Servo_ImportRule_GetSheet,
-                   RawServoStyleSheetStrong,
-                   const RawServoImportRuleBorrowed import_rule)
 SERVO_BINDING_FUNC(Servo_StyleSheet_ClearAndUpdate,
                    void,
                    RawServoStyleSheetBorrowed stylesheet,