⛽ Pre-warm the tab list file.

Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

- Switch migration task to use the thread pool executor.

- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

- Remove old UMA stat.

BUG=612574
Committed: https://crrev.com/bda78ff1475ff7e24fa57ed2e25924ee49af0d7b
Cr-Commit-Position: refs/heads/master@{#396343}

[Peter Wen, 2016-05-19 19:17:09]

Description was changed from

==========
Prevent duplicate migrations.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

BUG=612574
==========

to

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.
- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

BUG=612574
==========

[Peter Wen, 2016-05-19 19:17:42]

Description was changed from

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.
- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

BUG=612574
==========

to

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.
- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.
- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

BUG=612574
==========

[Peter Wen, 2016-05-19 19:19:28]

Description was changed from

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.
- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.
- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

BUG=612574
==========

to

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.
- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.
- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.
- Remove old UMA stat.

BUG=612574
==========

[Peter Wen, 2016-05-19 19:20:40]

Description was changed from

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.
- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.
- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.
- Remove old UMA stat.

BUG=612574
==========

to

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

- Remove old UMA stat.

BUG=612574
==========

[Peter Wen, 2016-05-19 19:21:27]

wnwen@chromium.org changed reviewers:
+ dfalcantara@chromium.org

[Peter Wen, 2016-05-19 19:21:28]

❄

[Peter Wen, 2016-05-19 19:27:32]

Description was changed from

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

- Remove old UMA stat.

BUG=612574
==========

to

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

- Switch migration task to use the thread pool executor.

- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

- Remove old UMA stat.

BUG=612574
==========

[gone, 2016-05-20 00:05:59]

lgtm

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
File
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java
(right):

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:198:
startPreFetchTask();
startPrefetchTask

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:348:
long time2 = SystemClock.elapsedRealtime();
Can you think of another name than "time2"?

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:758:
// max tab id. Thus allowing this to be done on the UI thread.
Maybe?

// Calculation of the max tab ID is done only once per user and is stored in
// SharedPreferences afterwards.  This is done on the UI thread because it is
// on the critical patch to initializing the TabIdManager with the correct max
tab ID.

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:1123:
* Folder that all metadata for the TabModels should be located. Each
subdirectory stores info
More accurate:

Directory containing all data for TabModels.  Each subdirectory stores info
about different TabModelSelectors, including metadata about each TabModel and
TabStates for each of their tabs.

[Peter Wen, 2016-05-24 12:22:28]

wnwen@chromium.org changed reviewers:
+ holte@chromium.org

[Peter Wen, 2016-05-24 12:22:29]

Thanks for the review, Dan!

+holte@ for histogram OWNERS.

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
File
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java
(right):

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:198:
startPreFetchTask();
On 2016/05/20 00:05:59, dfalcantara wrote:
> startPrefetchTask

Done.

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:348:
long time2 = SystemClock.elapsedRealtime();
On 2016/05/20 00:05:59, dfalcantara wrote:
> Can you think of another name than "time2"?

Done.

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:758:
// max tab id. Thus allowing this to be done on the UI thread.
On 2016/05/20 00:05:59, dfalcantara wrote:
> Maybe?
> 
> // Calculation of the max tab ID is done only once per user and is stored in
> // SharedPreferences afterwards.  This is done on the UI thread because it is
> // on the critical patch to initializing the TabIdManager with the correct max
> tab ID.

Done.

https://codereview.chromium.org/1996613003/diff/60001/chrome/android/java/src...
chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java:1123:
* Folder that all metadata for the TabModels should be located. Each
subdirectory stores info
On 2016/05/20 00:05:59, dfalcantara wrote:
> More accurate:
> 
> Directory containing all data for TabModels.  Each subdirectory stores info
> about different TabModelSelectors, including metadata about each TabModel and
> TabStates for each of their tabs.

Done.

[Steven Holte, 2016-05-24 17:35:24]

https://codereview.chromium.org/1996613003/diff/80001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (left):

https://codereview.chromium.org/1996613003/diff/80001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:90770: -  <suffix
name="CleanupAllEncryptedTime"/>
It's preferred to mark the suffix as obsolete, rather than deleting it, since it
is still sent by older versions of chrome.

[Peter Wen, 2016-05-24 19:19:34]

https://codereview.chromium.org/1996613003/diff/80001/tools/metrics/histogram...
File tools/metrics/histograms/histograms.xml (left):

https://codereview.chromium.org/1996613003/diff/80001/tools/metrics/histogram...
tools/metrics/histograms/histograms.xml:90770: -  <suffix
name="CleanupAllEncryptedTime"/>
On 2016/05/24 17:35:24, Steven Holte wrote:
> It's preferred to mark the suffix as obsolete, rather than deleting it, since
it
> is still sent by older versions of chrome.

Done.

[Peter Wen, 2016-05-25 12:56:15]

The CQ bit was checked by wnwen@chromium.org

[Peter Wen, 2016-05-25 12:56:16]

The patchset sent to the CQ was uploaded after l-g-t-m from
dfalcantara@chromium.org
Link to the patchset: https://codereview.chromium.org/1996613003/#ps100001
(title: "Marked as obsolete.")

[Peter Wen, 2016-05-25 12:56:16]

The CQ bit was unchecked by wnwen@chromium.org

[Peter Wen, 2016-05-26 15:51:24]

Friendly ping for histogram OWNERS. ❄

[Steven Holte, 2016-05-26 19:48:21]

lgtm, sorry for delay

[Peter Wen, 2016-05-26 21:07:56]

The CQ bit was checked by wnwen@chromium.org

[commit-bot: I haz the power, 2016-05-26 21:08:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1996613003/100001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1996613003/100001

[commit-bot: I haz the power, 2016-05-27 01:18:59]

Committed patchset #6 (id:100001)

[commit-bot: I haz the power, 2016-05-27 01:21:13]

Description was changed from

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

- Switch migration task to use the thread pool executor.

- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

- Remove old UMA stat.

BUG=612574
==========

to

==========
Pre-warm the tab list file.

- Store a SharedPreference boolean to prevent repeatedly checking
  whether the same user needs to be migrated from the old tab state
  file storage.

- Switch migration task to use the thread pool executor.

- Add a pre-fetch task to start reading the main tab list metadata
  file into a byte stream upon construction.

- Add UMA stats to track how long it takes for loadState to wait for
  the completion of the pre-fetch task.

- Remove old UMA stat.

BUG=612574

Committed: https://crrev.com/bda78ff1475ff7e24fa57ed2e25924ee49af0d7b
Cr-Commit-Position: refs/heads/master@{#396343}
==========

[commit-bot: I haz the power, 2016-05-27 01:21:15]

Patchset 6 (id:??) landed as
https://crrev.com/bda78ff1475ff7e24fa57ed2e25924ee49af0d7b
Cr-Commit-Position: refs/heads/master@{#396343}