Adds a method to the Performance Monitor Database to fetch the most recent metric.

Adds a method to the Performance Monitor Database to fetch the most recent metric.

BUG=130212
TEST=database_unittest gets the most recent metric


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=149668

[eaugusti, 2012-07-31 18:46:06]

https://chromiumcodereview.appspot.com/10843010/diff/4001/chrome/browser/perf...
File chrome/browser/performance_monitor/database.cc (right):

https://chromiumcodereview.appspot.com/10843010/diff/4001/chrome/browser/perf...
chrome/browser/performance_monitor/database.cc:390: std::string recent_start_key
= recent_map_[recent_map_key];
Not really a "start" key, just a key.

https://chromiumcodereview.appspot.com/10843010/diff/4001/chrome/browser/perf...
chrome/browser/performance_monitor/database.cc:392:
scoped_ptr<leveldb::Iterator> it(recent_db_->NewIterator(read_options_));
Maybe use Get() instead of an iterator:
http://leveldb.googlecode.com/svn/trunk/doc/index.html

You will have to check, but I think that it will return a status !s.ok() if the
key doesn't exist.

[chebert, 2012-07-31 19:26:35]

https://chromiumcodereview.appspot.com/10843010/diff/4001/chrome/browser/perf...
File chrome/browser/performance_monitor/database.cc (right):

https://chromiumcodereview.appspot.com/10843010/diff/4001/chrome/browser/perf...
chrome/browser/performance_monitor/database.cc:390: std::string recent_start_key
= recent_map_[recent_map_key];
On 2012/07/31 18:46:06, eaugusti wrote:
> Not really a "start" key, just a key.

Done.

https://chromiumcodereview.appspot.com/10843010/diff/4001/chrome/browser/perf...
chrome/browser/performance_monitor/database.cc:392:
scoped_ptr<leveldb::Iterator> it(recent_db_->NewIterator(read_options_));
On 2012/07/31 18:46:06, eaugusti wrote:
> Maybe use Get() instead of an iterator:
> http://leveldb.googlecode.com/svn/trunk/doc/index.html
> 
> You will have to check, but I think that it will return a status !s.ok() if
the
> key doesn't exist.

Done.

[eaugusti, 2012-07-31 19:38:52]

lgtm

[chebert, 2012-07-31 21:23:49]

Yoz, would you mind reviewing this when you get a chance?

[Yoyo Zhou, 2012-08-02 11:54:57]

LGTM, only minor changes requested

http://codereview.chromium.org/10843010/diff/5/chrome/browser/performance_mon...
File chrome/browser/performance_monitor/database.cc (right):

http://codereview.chromium.org/10843010/diff/5/chrome/browser/performance_mon...
chrome/browser/performance_monitor/database.cc:388: if
(!recent_map_.count(recent_map_key))
Use ContainsKey from stl_util.h.

http://codereview.chromium.org/10843010/diff/5/chrome/browser/performance_mon...
File chrome/browser/performance_monitor/database_unittest.cc (right):

http://codereview.chromium.org/10843010/diff/5/chrome/browser/performance_mon...
chrome/browser/performance_monitor/database_unittest.cc:302:
db->set_clock(scoped_ptr<Database::Clock>(clock2));
Just inline new TestingClock() here.

[commit-bot: I haz the power, 2012-08-02 17:24:26]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hebert.christopherj@chromium.org/10843...

[commit-bot: I haz the power, 2012-08-02 19:13:16]

Change committed as 149668