Revert 157080 "Report more details in heap snapshot progress ind..."

It broke the following tests on all platforms:

  inspector-protocol/heap-profiler/heap-snapshot-with-event-listener.html [ Failure ]
  inspector/profiler/heap-snapshot-loader.html [ Failure ]
  inspector/profiler/heap-snapshot.html [ Failure ]

> Report more details in heap snapshot progress indicator
> 
> When loading heap snapshot (either from file or backend) report separate progress for loading nodes, edges, strings and each processing step.
> 
> BUG=None
> R=loislo@chromium.org
> 
> Review URL: https://codereview.chromium.org/23717022

TBR=yurys@chromium.org

Review URL: https://codereview.chromium.org/23536011

git-svn-id: svn://svn.chromium.org/blink/trunk@157093 bbb929c8-8fbe-4397-9dbb-9b2b20218538