[MD settings] adding c++ side of clear browsing data

This CL is based on options version of same code/feature.
The counter and notification about incognito is not
yet included.

BUG=532739

Review URL: https://codereview.chromium.org/1367533003

Cr-Commit-Position: refs/heads/master@{#350434}
SettingsPageUIHandler::~SettingsPageUIHandler() {
}

SettingsPageUIHandler::~SettingsPageUIHandler() {
}
