GitLab

Make constrained window use embedder's native window
(through its WebContents) instead of using webview's.

After print preview got enabled by default, the code
trying to bring up print preview dialog (a constrained
window) started crashing the browser.

BUG=286487
Test=In chromeos device/LinuxAura/Mac: load the sample
browser app
https://github.com/GoogleChrome/chrome-app-samples/tree/master/webview-samples/browser
Navigate to a page that calls window.print()
http://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_print
Click "Print this page" to trigger window.print() inside
webview.
It should
1) not crash
2) correctly show the preview and print the contents of
the webview, not the entire app. This
means it shouldn't print the chrome (address bar/buttons etc.)
of the browser sample.

Review URL: https://codereview.chromium.org/321193003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276372 0039d316-1c4b-4281-b951-d872f2087c98