[usecase-embeddingapi] Improve XWalkPrefere and multi views usecase

- Improve MultiSurfaceViewsActivity, MultiTextureViewsActivity and XWalkPrefere

Impacted tests(approved): new 0, update 3, delete 0
Unit test platform: [Android]
Unit test result summary: pass 3, fail 0, block 0
Merge pull request #974 from zhuyongyong/yongzhu/usecase-embeddingapi/improveInfo

[usecase-embeddingapi] Improve XWalkPrefere and multi views usecase