aw: Disable hardware features for software layer

If the webview is put into a software layer, then disable hardware only
features such as accelerated canvas even if we are attached to a
hardware view tree.

Previously we did not take layer type into account.

BUG=332273

Review URL: https://codereview.chromium.org/199573002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257037 0039d316-1c4b-4281-b951-d872f2087c98
Add app install banner UMA stats

Adds UMA for various app banner related events, like clicking on the banner or clicking on the button.

The code actually adding to the histograms metrics was pulled out of this CL for clarity.

BUG=341556

Review URL: https://codereview.chromium.org/195233004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257038 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257037
SVN changes up to revision 257038
Register Files.app as the handler of .svg files.

BUG=352283
R=hirono@chromium.org

Review URL: https://codereview.chromium.org/199823002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257039 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 257039