Precache: Optionally rank resources-to-precache globally.

Precache: Optionally rank resources-to-precache globally.

Added a new global_ranking varation param to the experiment, default false. If
specified, the client will multiply each resource weight (a value [0,1]) from
the PrecacheManifest by the number of visits to that host -- the result being
an estimated likelihood of using that resource. The resources will then be
fetched in decreasing order of likelihood.

This allows hosts with vastly more visits to fetch more resources than hosts
with vastly fewer visits. It also allows mostly-useless resources to bubble
down and be replaced by resources for additional hosts.

In addition, added a couple new fields to PrecacheConfigurationSettings to
tweak its behavior:
- total_resources_count is a cap on the total number of resource URLs to fetch
- min_weight is a threshold on the minimum likelihood

In addition, a few things changed in behavior:
- manifests are fetched first, before any resources
- the PercentCompleted UMA is measured in % of resource URLs complete rather
  than % of manifests complete
- resource ordering is preserved across pause/resume

BUG=654166
Review-Url: https://chromiumcodereview.appspot.com/2403193002
Cr-Commit-Position: refs/heads/master@{#426350}
(cherry picked from commit 528a15b56652173bd822ea2a1123e6960ba4f255)

Committed: https://chromium.googlesource.com/chromium/src/+/04fc59a0ca84731499f804d2c3aa9fafe4132e06

[twifkak, 2016-10-20 01:57:32]

Description was changed from

==========
Precache: Optionally rank resources-to-precache globally.

Added a new global_ranking varation param to the experiment, default false. If
specified, the client will multiply each resource weight (a value [0,1]) from
the PrecacheManifest by the number of visits to that host -- the result being
an estimated likelihood of using that resource. The resources will then be
fetched in decreasing order of likelihood.

This allows hosts with vastly more visits to fetch more resources than hosts
with vastly fewer visits. It also allows mostly-useless resources to bubble
down and be replaced by resources for additional hosts.

In addition, added a couple new fields to PrecacheConfigurationSettings to
tweak its behavior:
- total_resources_count is a cap on the total number of resource URLs to fetch
- min_weight is a threshold on the minimum likelihood

In addition, a few things changed in behavior:
- manifests are fetched first, before any resources
- the PercentCompleted UMA is measured in % of resource URLs complete rather
  than % of manifests complete
- resource ordering is preserved across pause/resume

BUG=654166

Review-Url: https://chromiumcodereview.appspot.com/2403193002
Cr-Commit-Position: refs/heads/master@{#426350}
(cherry picked from commit 528a15b56652173bd822ea2a1123e6960ba4f255)
==========

to

==========
Precache: Optionally rank resources-to-precache globally.

Added a new global_ranking varation param to the experiment, default false. If
specified, the client will multiply each resource weight (a value [0,1]) from
the PrecacheManifest by the number of visits to that host -- the result being
an estimated likelihood of using that resource. The resources will then be
fetched in decreasing order of likelihood.

This allows hosts with vastly more visits to fetch more resources than hosts
with vastly fewer visits. It also allows mostly-useless resources to bubble
down and be replaced by resources for additional hosts.

In addition, added a couple new fields to PrecacheConfigurationSettings to
tweak its behavior:
- total_resources_count is a cap on the total number of resource URLs to fetch
- min_weight is a threshold on the minimum likelihood

In addition, a few things changed in behavior:
- manifests are fetched first, before any resources
- the PercentCompleted UMA is measured in % of resource URLs complete rather
  than % of manifests complete
- resource ordering is preserved across pause/resume

BUG=654166

Review-Url: https://chromiumcodereview.appspot.com/2403193002
Cr-Commit-Position: refs/heads/master@{#426350}
(cherry picked from commit 528a15b56652173bd822ea2a1123e6960ba4f255)

Committed:
https://chromium.googlesource.com/chromium/src/+/04fc59a0ca84731499f804d2c3aa...
==========

[twifkak, 2016-10-20 01:57:33]

Committed patchset #1 (id:1) manually as
04fc59a0ca84731499f804d2c3aa9fafe4132e06.