Negate HTMLInputElement::m_valueMatchesRenderer and rename it to m_needsToUpdateViewValue.

The flag name was obsolete. A renderer doesn't have the value nowadays. This CL
renames it to more concrete one.

The flag is referred only by text field types. So we can remove the public
setter function and its callsite in FileInputType.

BUG=342430
TEST=none; no behavior changes.

Review URL: https://codereview.chromium.org/228213002

git-svn-id: svn://svn.chromium.org/blink/trunk@171041 bbb929c8-8fbe-4397-9dbb-9b2b20218538