Correctly set the viewport in layers.

Bug #2919295

Change-Id: I16ce79ab0d5747cb01c6c1abe531da3dfd93fb54
diff --git a/libs/hwui/TextDropShadowCache.h b/libs/hwui/TextDropShadowCache.h
index 9c86187..5fbe9e5 100644
--- a/libs/hwui/TextDropShadowCache.h
+++ b/libs/hwui/TextDropShadowCache.h
@@ -47,7 +47,7 @@
 
     ShadowText(const ShadowText& shadow):
             paint(shadow.paint), radius(shadow.radius), len(shadow.len), hash(shadow.hash) {
-        text = new char[len];
+        text = new char[shadow.len];
         memcpy(text, shadow.text, shadow.len);
     }