apkpatch工具类diff 方法 新增类 执行不到的问题，见注释

com.euler.patch.diff 包下DexDiffer类。

```
public DiffInfo diff(File newFile, File oldFile)
throws IOException
{
DexBackedDexFile newDexFile = DexFileFactory.loadDexFile(newFile, 19,
true);
DexBackedDexFile oldDexFile = DexFileFactory.loadDexFile(oldFile, 19,
true);
DiffInfo info = DiffInfo.getInstance();
//此行代码是否应该放入第一个for循环中，每次遍历都重置一下状态
boolean contains = false;
for (DexBackedClassDef newClazz : newDexFile.getClasses()) {
Set oldclasses = oldDexFile
.getClasses();
for (DexBackedClassDef oldClazz : oldclasses) {
if (newClazz.equals(oldClazz)) {
compareField(newClazz, oldClazz, info);
compareMethod(newClazz, oldClazz, info);
contains = true;
break;
}
}
//1、场景是现在类有修改、并且有新增类
if (contains)
continue;
//即使有新增类这里也不会被执行到。
info.addAddedClasses(newClazz);
}

return info;
}
```

Start in com.euler.patch.diff.DexDiffer at diff(File newFile, File oldFile), then trace the contains flag and the calls to compareField, compareMethod, and addAddedClasses. Reproduce the stated case where a modified class and a newly added class coexist; done means both the modified-class comparison and new-class recording occur.

Written by the indexing model from the issue text.