Merge "Clear native shader when Paint shader changes" into oc-dev

am: d3e78478aa

Change-Id: I8d9c87e232ee1bbc77f3c5618f5856e891c78a74

graphics/java/android/graphics/Paint.java

@@ -1036,6 +1036,8 @@ public class Paint {
         // old shader's pointer may be reused by another shader allocation later
         if (mShader != shader) {
             mNativeShader = -1;
+            // Release any native references to the old shader content
+            nSetShader(mNativePaint, 0);
         }
         // Defer setting the shader natively until getNativeInstance() is called
         mShader = shader;