DevTools: Search should use the last query by default.

Current selection is not used as a default query anymore when it is empty.

Added shouldJump parameter to performSearch method. This is needed because
while search should be started immediately when search field is opened with
the last query available, we don't want to jump to results until explicit
user action. Otherwise users might lose their context in case they wanted
to perform a search with another query.

Increased search matches message size to fit new "42 matches" message shown when the search was
already performed but no result is shown yet.

Removed unneeded showPanelForAnchorNavigation and disableSearchUntilExplicitAction methods.

R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/17583022

git-svn-id: svn://svn.chromium.org/blink/trunk@153006 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove SVGLangSpace IDL interface

Remove SVGLangSpace IDL interface and move its attributes to SVGElement
to match the latest specification and simplify inheritance in SVG:
https://svgwg.org/svg2-draft/types.html#InterfaceSVGElement

BUG=253477

Review URL: https://chromiumcodereview.appspot.com/17608010

git-svn-id: svn://svn.chromium.org/blink/trunk@153007 bbb929c8-8fbe-4397-9dbb-9b2b20218538