Reduce the number of active texture changes

Change-Id: I94046bdfe20740c26c8183822e3002d692fde7c4
diff --git a/libs/hwui/Program.h b/libs/hwui/Program.h
index 559c717..eed909d 100644
--- a/libs/hwui/Program.h
+++ b/libs/hwui/Program.h
@@ -398,6 +398,8 @@
 
     bool mHasColorUniform;
     int mColorUniform;
+
+    bool mHasSampler;
 }; // class Program
 
 }; // namespace uirenderer