VideoCaptureController: add UMA AspectRatio histogram.

This is a follow-up of "Issue 177003019: Add video 
capture UMA histograms: width, height, frame rate, 
pixel format.", adding the UMA histogram sampling 
aspect ratio. The aspect ratio is calculated and 
sampled using UMA_HISTOGRAM_ASPECT_RATIO(), which is
a forwarding to UMA_HISTOGRAM_SPARSE_SLOWLY().

BUG=309554

TBR=wjia@chromium.org

Review URL: https://codereview.chromium.org/185233014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256202 0039d316-1c4b-4281-b951-d872f2087c98
User manager action box dropdown shouldn't trigger pod events.

BUG=350309
TEST=With --new-profile-management enabled, click on "View all people"
to show the user manager. Click on a user pod's dropdown arrow. This should
show the action box. Click on the arrow again. This should hide the action
box, keep the user manager open and not launch the pod's profile

Review URL: https://codereview.chromium.org/190633005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256203 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256203
Small refactor to memory_inspector.

Some small architectural changes required for the upcoming www UI.
The main change introduced by this CL is moving the deps inclusion 
from run_tests to the main module initializer.
Rationale: in the next cl, a new binary (start_web_ui) will need to
include the same deps, so moving that to a common place.

BUG=340294
NOTRY=true

Review URL: https://codereview.chromium.org/192033003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256204 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256204