Add perf markers in XMLHttpRequest
Add perf markers in XMLHttpRequest

Summary:
ChangeLog: [Both] Adds perf markers for `XMLHttpRequest`s

Makes it easier to see JS-based network operations in performance traces.

Reviewed By: zackargyle

Differential Revision: D19903143

fbshipit-source-id: c5ce60163569e003830d8079cb2b580469d5bd5d

pandiaraj44/react-native,javache/react-native,hammerandchisel/react-native,facebook/react-native,javache/react-native,exponent/react-native,pandiaraj44/react-native,exponentjs/react-native,myntra/react-native,myntra/react-native,arthuralee/react-native,facebook/react-native,exponent/react-native,myntra/react-native,facebook/react-native,janicduplessis/react-native,hoangpham95/react-native,pandiaraj44/react-native,myntra/react-native,arthuralee/react-native,exponent/react-native,janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,hammerandchisel/react-native,facebook/react-native,exponentjs/react-native,javache/react-native,hammerandchisel/react-native,janicduplessis/react-native,hammerandchisel/react-native,myntra/react-native,exponentjs/react-native,exponent/react-native,pandiaraj44/react-native,myntra/react-native,exponentjs/react-native,exponentjs/react-native,janicduplessis/react-native,hoangpham95/react-native,exponentjs/react-native,hammerandchisel/react-native,exponent/react-native,hoangpham95/react-native,facebook/react-native,hammerandchisel/react-native,janicduplessis/react-native,javache/react-native,javache/react-native,janicduplessis/react-native,javache/react-native,javache/react-native,hoangpham95/react-native,pandiaraj44/react-native,arthuralee/react-native,hoangpham95/react-native,exponent/react-native,janicduplessis/react-native,exponentjs/react-native,myntra/react-native,javache/react-native,hoangpham95/react-native,exponent/react-native,pandiaraj44/react-native,pandiaraj44/react-native,hoangpham95/react-native,hammerandchisel/react-native,arthuralee/react-native,facebook/react-native,myntra/react-native,hammerandchisel/react-native,facebook/react-native,pandiaraj44/react-native,javache/react-native,myntra/react-native,exponentjs/react-native,arthuralee/react-native,hoangpham95/react-native,exponent/react-native,facebook/react-native