DevTools: [ConsoleView] Use in  its internal structures (visibleMessages, searchResults) consoleViewMessages instead  of indices of consoleMessages in model

BUG=

Review URL: https://codereview.chromium.org/196283011

git-svn-id: svn://svn.chromium.org/blink/trunk@169134 bbb929c8-8fbe-4397-9dbb-9b2b20218538