GitLab

- Fix virtual vs resident size reporting in the "size" column:
  Prior to this change the PartitionAlloc dumper was reporting the
  mmap-ed (virtual address spave) size in the "size" column.
  This is inconsistent with the rest of the dumpers, which strive
  to report an estimation of actually resident memory in the "size"
  column.
  This change moves the PA resident size into "size".   
- Remove the "thread_1234" sub-node: turns out that there can be at
  most one PartitionAlloc instance per-process, even in single-process
  mode.
- Improve reporting of allocated_objects:
  - Each bucket gets a column "allocated_objects_size", previously 
    called "active_size" (confusing), which reports the size of bytes
    requested by PA clients.
  - The per-bucket "allocated_objects" sub-rows are removed: they just
    added visual clutter and didn't add any extra information than an
    extra column.
  - A global allocated_objects node is introduced. This will be required
    by subsequent CLs to properly account memory reporter by other pieces
    of blink. This will be to avoid that WebCache memory that is 
    allocated via PA gets double-counted in the effective_size.
- Improve other column names for sake of clarity:
   - committed -> virtual_committed
   - num_{active,full,...} -> {active,full,...}_pages. The previous name
     didn't make it clear that they count pages and not objects.

BUG=488472

Review URL: https://codereview.chromium.org/1312843010

git-svn-id: svn://svn.chromium.org/blink/trunk@201972 bbb929c8-8fbe-4397-9dbb-9b2b20218538