Remove unused and dangerous Event::cloneFor functions

These functions were added in http://src.chromium.org/viewvc/blink?revision=126256&view=revision
to support seamless iframes, but aren't reachable. They are dangerous since they produce Events
with type()s that do not match the actual type of the object.

BUG=244882

Review URL: https://chromiumcodereview.appspot.com/17912006

git-svn-id: svn://svn.chromium.org/blink/trunk@153117 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Introduce toWorkerGlobalScope, and use it.

Also, remove unnecessary assertions. toWorkerGlobalScope asserts
isWorkerGlobalScope.

BUG=

Review URL: https://chromiumcodereview.appspot.com/18004003

git-svn-id: svn://svn.chromium.org/blink/trunk@153118 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix border radius glitch.

This fixes the bug that the border radius partially disappeared or had wrong color when it was too steep or too shallow.

Fix 1: Use the correct clipping quad, generated by intersecting border mitre lines to diagonal lines of the corner ellipse arc.
RenderBoxModelObject::clipBorderSidePolygon was generating wrong clipping quad.
It was based on a wrong assumption that rounded border would not cross {horizontal,vertical} line through the box center.

Fix 2: Correctly split a quad into two quads.
A clipping quad is split into "AND" of two quads to set anti-aliasing on both edges individually.
Generate these quads properly by extending a vertex parallel to the opposite edge.

TEST=LayoutTests/fast/borders/*
BUG=160239
BUG=244748
R=jchaffraix@chromium.org, tasak@google.com

Review URL: https://codereview.chromium.org/15804009

git-svn-id: svn://svn.chromium.org/blink/trunk@153119 bbb929c8-8fbe-4397-9dbb-9b2b20218538
This patch adds
 - moveParagraphBackward/movePargraphForward to document.execCommand()
 - Key bindings (Ctrl+Up/Down) for them for Windows.

BUG=38097
R=tkent@chromium.org

Review URL: https://codereview.chromium.org/17828002

git-svn-id: svn://svn.chromium.org/blink/trunk@153120 bbb929c8-8fbe-4397-9dbb-9b2b20218538