Implement new invalidations ack tracking system

Enable the new invalidation ack tracking API.  This system allows the
invalidations system to remember invalidations that have not been acted upon
yet across browser restarts.

New features include:
- Supports saving multiple invalidation payloads per ObjectID.
- Supports tracking lost or dropped invalidations.
- Remembers "unknown version" invalidations across restarts.
- Can send multiple payloads in a single callback.
- Does not periodically ping unacked invalidations.

A series of commits prior to this one have put much of the framework in place
already.  This CL does not change the types and signatures of client-facing
APIs very much, but it does enable perviously disbaled behavior.  This CL
includes updates to the client code to allow them to support the new semantics
with (hopefully) few changes to externally visible behavior.

Most of the big changes are in the classes and tests associated with the
internals of Invalidations.  Large parts of the SyncInvalidationListener and
InvalidatorStorage have been rewritten.

BUG=233437

Review URL: https://codereview.chromium.org/56113003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237421 0039d316-1c4b-4281-b951-d872f2087c98
Use SpdyMajorVersion instead of int consistently
as the data type to describe the SPDY version.

Review URL: https://codereview.chromium.org/88693002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237422 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237422
Suppress the STEP_SUCCESS unsupported annotation in check_ecs_deps.

R=spang@chromium.org
BUG=None
TEST=local

Review URL: https://codereview.chromium.org/88913005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237423 0039d316-1c4b-4281-b951-d872f2087c98
Remove unused IndexedDB valgrind suppressions

Via the build logs, bug_252641_b hasn't been needed since Sept 23rd
and bug_252228 hasn't been needed since Nov 4th.

BUG=252641,293024
TBR=thestig@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/89453002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237424 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237424