Exclude dev tools bounds from views dialog hosting bounds.

Add BrowserViewLayoutDelegate::GetContentsWebView helper.
(avoids direct BrowserView usage by BrowserViewLayout)
Consider the latest dialog position *AND* size on updates.
(previously, the maximum dialog size was incorrectly ignored)
Only use the contents WebView bounds, not its container.
(the container also includes the dev tools view bounds)
Minor BrowserViewLayout cleanup and refactoring.

BUG=328798
TEST=Collected Cookies and Print Preview dialogs resize as the web tools height is manually adjusted.
R=ben@chromium.org

Review URL: https://codereview.chromium.org/99153012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243168 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243168