fix destructor order to fix build

src/pathops/SkPathOpsCommon.cpp

Index: src/pathops/SkPathOpsCommon.cpp
diff --git a/src/pathops/SkPathOpsCommon.cpp b/src/pathops/SkPathOpsCommon.cpp
index b0fd822a9d359d08ca8f378b71e8551a466f011c..1dc171caf35864de04b712f85a96e467776a41b5 100644
--- a/src/pathops/SkPathOpsCommon.cpp
+++ b/src/pathops/SkPathOpsCommon.cpp
@@ -440,12 +440,12 @@ public:
         reassemble contour pieces into new path
     */
 void Assemble(const SkPathWriter& path, SkPathWriter* simple) {
+    SkChunkAlloc allocator(4096);  // FIXME: constant-ize, tune
     SkOpContour contour;
     SkOpGlobalState globalState(NULL  PATH_OPS_DEBUG_PARAMS(&contour));
 #if DEBUG_PATH_CONSTRUCTION
     SkDebugf("%s\n", __FUNCTION__);
 #endif
-    SkChunkAlloc allocator(4096);  // FIXME: constant-ize, tune
     SkOpEdgeBuilder builder(path, &contour, &allocator, &globalState);
     builder.finish(&allocator);
     SkTDArray<const SkOpContour* > runs;  // indices of partial contours