Make top layer elements occlude plugins.

Before this patch, native plugins such as Flash would always be rendered
above top layer elements.  This patch adds top layer elements to the
cutout rects for a plugin, that were already generated for the "iframe
shim" mechanism.

This patch requires manual tests because content_shell doesn't seem to
handle plugins well (crbug.com/285780). As a result, a conventional
LayoutTest would pass with or without this patch.

This patch does not yet correctly handle interaction between iframes and
top layer when occluding the plugin. For example, an iframe will still
occlude a plugin in the top layer, since the existing code for only
examines zindex, not top layer.

Another flaw is that the plugin cannot be shown under an element with
a translucent background; the plugin is completely occluded.

BUG=285775

Review URL: https://chromiumcodereview.appspot.com/23494031

git-svn-id: svn://svn.chromium.org/blink/trunk@158001 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make CompositeEditCommand::prepareWhitespaceAtPositionForSplit() works at deleting SVG element

CompositeEditCommand::prepareWhitespaceAtPositionForSplit() replaces collapsible whitespaces with non-breaking space around split position.

This patch changes it to work when split position is end of text node, e.g. VisualPosition.downstream().deprecatedNode() != VisualPostion.deprecateNode().

BUG=252093
TEST=LayoutTests/editing/deleting/delete-svg-001.html
R=ojan@chromium.org

Review URL: https://codereview.chromium.org/17483003

git-svn-id: svn://svn.chromium.org/blink/trunk@158002 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove Vector reallocation code.

Replace the only usage with a simpler, faster optimization.
(The optimization isn't huge, it only triggers 5 times during NTP load.)

Review URL: https://chromiumcodereview.appspot.com/23475056

git-svn-id: svn://svn.chromium.org/blink/trunk@158003 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Refactoring: Move queryLocalizedString() to Locale class.

They always return strings for browser UI locale for now. We'd like to
update them so that they return locale-dependent strings in the future.

Also, remove unused functions of LocalizedStrings.

BUG=161733
TEST=none; no behavior changes.

Review URL: https://chromiumcodereview.appspot.com/24201005

git-svn-id: svn://svn.chromium.org/blink/trunk@158004 bbb929c8-8fbe-4397-9dbb-9b2b20218538