Fix potential npe

bug 19805515

Change-Id: Id36b145d3ce1c81311e88f5cdd2441880e98f737
diff --git a/rs/java/android/renderscript/Mesh.java b/rs/java/android/renderscript/Mesh.java
index 5b4cadb..13c8e1c 100644
--- a/rs/java/android/renderscript/Mesh.java
+++ b/rs/java/android/renderscript/Mesh.java
@@ -363,6 +363,9 @@
                     alloc = Allocation.createTyped(mRS, entry.t, mUsage);
                 } else if(entry.e != null) {
                     alloc = Allocation.createSized(mRS, entry.e, entry.size, mUsage);
+                } else {
+                    // Should never happen because the builder will always set one
+                    throw new IllegalStateException("Builder corrupt, no valid element in entry.");
                 }
                 vertexBuffers[ct] = alloc;
                 vtx[ct] = alloc.getID(mRS);
@@ -375,6 +378,9 @@
                     alloc = Allocation.createTyped(mRS, entry.t, mUsage);
                 } else if(entry.e != null) {
                     alloc = Allocation.createSized(mRS, entry.e, entry.size, mUsage);
+                } else {
+                    // Should never happen because the builder will always set one
+                    throw new IllegalStateException("Builder corrupt, no valid element in entry.");
                 }
                 long allocID = (alloc == null) ? 0 : alloc.getID(mRS);
                 indexBuffers[ct] = alloc;