Refactoring: Move m_mayDisplaySeamlesslyWithParent down to Document

The member is used only in Document, thus no reason to
stay in SecurityContext.

TEST=none
BUG=none
R=haraken@chromium.org, abarth, haraken, hayato

Review URL: https://codereview.chromium.org/27615003

git-svn-id: svn://svn.chromium.org/blink/trunk@159829 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Frame* Document::findUnsafeParentScrollPropagationBoundary()
{
    Frame* currentFrame = m_frame;
    Frame* ancestorFrame = currentFrame->tree()->parent();

    while (ancestorFrame) {
        if (!ancestorFrame->document()->securityOrigin()->canAccess(securityOrigin()))
            return currentFrame;
        currentFrame = ancestorFrame;
        ancestorFrame = ancestorFrame->tree()->parent();
    }
    return 0;
}

Frame* Document::findUnsafeParentScrollPropagationBoundary()
{
    Frame* currentFrame = m_frame;
    Frame* ancestorFrame = currentFrame->tree()->parent();

    while (ancestorFrame) {
        if (!ancestorFrame->document()->securityOrigin()->canAccess(securityOrigin()))
            return currentFrame;
        currentFrame = ancestorFrame;
        ancestorFrame = ancestorFrame->tree()->parent();
    }
    return 0;
}
