Set/override WebContents preferred size during tab capture.

During tab capture, the preferred size of a WebContents will be the video resolution of the capture.  In upcoming changes, views will use this as a target for sizing a fullscreen widget embedded within a tab; meant to prevent additional detrimental scalings of the content.

The normal "contents preferred size" is provided by blink::WebView and propagated from the renderer to browser process, ultimately into WebContentsImpl.  Currently, the only consumer of the value is the Cocoa browser window controller, where it is an input to the calculation that determines the "standard size" of the window (when the user clicks the window's zoom button).  Thus, for this single existing use case, it is both reasonable and desirable for tab capture to override the WebContents' preferred size.

BUG=256870
R=imcheng@chromium.org, joi@chromium.org, sky@chromium.org
TBR=shishir@chromium.org

Review URL: https://codereview.chromium.org/148583011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249155 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249155
Fix window opening in Feedback.
Component apps can no longer use the chrome.windows extension API. Change them to use the chrome apps windowing API instead.
We cannot use window.open here since window.open fails on chrome:// pages (expected behavior; due to security reasons).

R=xiyuan@chromium.org
BUG=338769

Review URL: https://codereview.chromium.org/154003005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249157 0039d316-1c4b-4281-b951-d872f2087c98
Disable noisy printf in external_metrics.cc

This is printed in every browser test, and just adds noise. Switch it
to VLOG(1) so it's available when wanted.

R=davemoore@chromium.org
BUG=339891

Review URL: https://codereview.chromium.org/151703004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249158 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249158