DOMUI Prefs: willHidePage() called always before hiding a page.
DOMUI Prefs: willHidePage() called always before hiding a page.

willHidePage() now called for preferences pages that are hidden due to Escape press or click on a top-level page, not only due to navigateToPage() call.

BUG=None
TEST=No observable changes in behaviour

Review URL: http://codereview.chromium.org/7830040

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@99640 0039d316-1c4b-4281-b951-d872f2087c98

yitian134/chromium,gavinp/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,yitian134/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,ropik/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,yitian134/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,ropik/chromium,ropik/chromium