add include to remove legacy flag

BUG=skia:

NOTRY=True

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4377

Change-Id: Ie3b173188041a8c37fc2252d257c1f3e1c2a4c84
Reviewed-on: https://skia-review.googlesource.com/4377
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/tools/android/SkAndroidSDKCanvas.cpp b/tools/android/SkAndroidSDKCanvas.cpp
index 4db8acd..887d416 100644
--- a/tools/android/SkAndroidSDKCanvas.cpp
+++ b/tools/android/SkAndroidSDKCanvas.cpp
@@ -9,6 +9,7 @@
 
 #include "SkColorFilter.h"
 #include "SkDrawLooper.h"
+#include "SkImageFilter.h"
 #include "SkPaint.h"
 #include "SkPathEffect.h"
 #include "SkShader.h"