Add 10 minute random fuzz to automatic update check event schedule.

Add 10 minute random fuzz to automatic update check event schedule.

Schedules the initial check at 7 minutes and periodic checks at 45 minutes
with +/- 5 minute fuzz.

BUG=5983
TEST=unit tests, gmerged on device, inspected logs, observed checks

Change-Id: Ifd38574c4265fec78f6e330f965c2b1054b2dddb

[adlr, 2010-08-24 19:28:14]

http://codereview.chromium.org/3173041/diff/1/2
File main.cc (right):

http://codereview.chromium.org/3173041/diff/1/2#newcode49
main.cc:49: LOG(INFO) << "Next update check: " << seconds << " seconds from
now.";
should we maybe get rid of this? Seems useful for debugging but not super
necessary for real use

http://codereview.chromium.org/3173041/diff/1/2#newcode123
main.cc:123: base::AtExitManager exit_manager;  // Required for
base/rand_util.h.
why is this needed (just curious)?

http://codereview.chromium.org/3173041/diff/1/3
File utils.cc (right):

http://codereview.chromium.org/3173041/diff/1/3#newcode463
utils.cc:463: int max = value + range - range / 2;
yeah, i guess you could just do
max = value + range / 2
right?

http://codereview.chromium.org/3173041/diff/1/4
File utils.h (right):

http://codereview.chromium.org/3173041/diff/1/4#newcode129
utils.h:129: // [value - range / 2, value + range - range / 2]
perhaps more concisely described:

[value - range / 2, value + range / 2]

http://codereview.chromium.org/3173041/diff/1/5
File utils_unittest.cc (right):

http://codereview.chromium.org/3173041/diff/1/5#newcode175
utils_unittest.cc:175: base::AtExitManager exit_manager;
maybe put this into testrunner.cc?

[petkov, 2010-08-24 19:52:20]

PTAL

http://codereview.chromium.org/3173041/diff/1/2
File main.cc (right):

http://codereview.chromium.org/3173041/diff/1/2#newcode49
main.cc:49: LOG(INFO) << "Next update check: " << seconds << " seconds from
now.";
On 2010/08/24 19:28:15, adlr wrote:
> should we maybe get rid of this? Seems useful for debugging but not super
> necessary for real use

I thought it might be useful for debugging field issues. Or maybe not...
Removed.

http://codereview.chromium.org/3173041/diff/1/2#newcode123
main.cc:123: base::AtExitManager exit_manager;  // Required for
base/rand_util.h.
On 2010/08/24 19:28:15, adlr wrote:
> why is this needed (just curious)?

rand_util uses a lazy_instance to open /dev/urandom on first use (and keep a
handle to the file). lazy_instance registers its destructor with the global
AtExitManager so that it closes the handle on exit. So, to use rand_util, you
need to create an exit manager.

http://codereview.chromium.org/3173041/diff/1/3
File utils.cc (right):

http://codereview.chromium.org/3173041/diff/1/3#newcode463
utils.cc:463: int max = value + range - range / 2;
On 2010/08/24 19:28:15, adlr wrote:
> yeah, i guess you could just do
> max = value + range / 2
> right?

Actually, I wanted to handle "correctly" odd ranges. For example, value with a
range of 1 will return values in the range

[value, value + 1]

If we simply do range/2, a range of 1 will always return |value| (just like
specifying a range of 0).

Makes sense? I can change it or document better?

http://codereview.chromium.org/3173041/diff/1/4
File utils.h (right):

http://codereview.chromium.org/3173041/diff/1/4#newcode129
utils.h:129: // [value - range / 2, value + range - range / 2]
On 2010/08/24 19:28:15, adlr wrote:
> perhaps more concisely described:
> 
> [value - range / 2, value + range / 2]

See below.

http://codereview.chromium.org/3173041/diff/1/5
File utils_unittest.cc (right):

http://codereview.chromium.org/3173041/diff/1/5#newcode175
utils_unittest.cc:175: base::AtExitManager exit_manager;
On 2010/08/24 19:28:15, adlr wrote:
> maybe put this into testrunner.cc?

Done.

[adlr, 2010-08-24 19:54:50]

LGTM thanks for the info