commit 8d93f0fabbd8c6383a650b64e758059117ff4ef1
author Wyatt Allen <wyatta@google.com> Fri May 11 13:10:08 2018 -0700
committer Wyatt Allen <wyatta@google.com> Mon May 14 15:01:06 2018 -0700
tree 110fb7da274124018302d06972bbbe23a497b586
parent 0af4aa9095cd204ae32cf297c0300ff738eac6ab

Measure and report time spent loading change data

The change view shows change information and enables interactivity
incrementally. The `gr-reporting#changeDisplayed` reports when the
change has become visible to the user (the "core-data" of the change has
loaded), but not necessarily all the change data (such as actions, file
list or comment data)

With this change, an additional report is added to track the time spent
loading the full set of change data. This may take more or less time
than the `changeDisplayed` timing:
- It will take more time if the non-core data is loaded slowly.
- It will take less time if the the core-data is rendered slowly.

To measure time spent loading all data, the `gr-change-view#_reload`
method is refactored.
- Before: some non-core data requests were started from within the
  promise chain, but their resolution was discarded, making them
  difficult to track without influencing resolution of the core-data
  promise.
- Instead: rather than bundling everything into a single big chain,
  individual dependency relations are separated and named in variables.
  This allows us to explicitly choose which are included in the
  core-data promise that's returned, and also which are included in the
  timing for the full set of change requests.

Change-Id: I69ebd7273b5724fd906392d255a412c262b48d05