Add SK_SUPPORT_LEGACY_DRAWFILTER guard around calls to SkCanvas::(get|set)DrawFilter.

tests/DrawFilterTest.cpp

Index: tests/DrawFilterTest.cpp
diff --git a/tests/DrawFilterTest.cpp b/tests/DrawFilterTest.cpp
index 6381a3c8fa158e00982f5688f655facca0bd8bce..f3e0a77306c8dba5e1267845371ca118be38132d 100644
--- a/tests/DrawFilterTest.cpp
+++ b/tests/DrawFilterTest.cpp
@@ -10,6 +10,8 @@
 #include "SkSurface.h"
 #include "Test.h"
 
+#ifdef SK_SUPPORT_LEGACY_DRAWFILTER
+
 namespace {
 class TestFilter : public SkDrawFilter {
 public:
@@ -43,3 +45,5 @@ static void test_saverestore(skiatest::Reporter* reporter) {
 DEF_TEST(DrawFilter, reporter) {
     test_saverestore(reporter);
 }
+
+#endif