[embedding][XWALK-1052] Add one line to import Method class

Impacted tests(approved): new 0, update 1, delete 0
Unit test platform: [Android]
Unit test result summary: pass 72, fail 17, block 4
Merge pull request #720 from zhuyongyong/yongzhu/embeddingAPI/improve

[embedding][XWALK-1052] Add one line to import Method class