Clarify javadocs for getBody() and getBodyContentType().

Change-Id: I83a538bb466b6fd7801961ef47952009bb0defdb
Merge "Clarify javadocs for getBody() and getBodyContentType()."
Metric for network time and getBackoffMultiplier()

Added networkTimeMs to both NetworkResponse and VolleyError.
Set the networkTimeMs in NetworkDispatcher
Added getter method for backoff multiplier of RetryPolicy.

Change-Id: Ief1e079642fea03fe9c4685bb87a29469ae4b8a7
Merge "Metric for network time and getBackoffMultiplier()"
Merge branch 'master' of https://android.googlesource.com/platform/frameworks/volley