Ignore visibility when checking whether Position is editable or not at DeletetSelectionCommand 

This patch introduces |lastEditablePositionBeforePositionInRoot()| to get
to editable |Position| instead of |VisiblePosition| for making
DeletetSelectionCommand to work editable position regardless its visibility.

The root cause of issue 339187 is |DeleteSelectionCommand| shrinks end point of 
selection range, start position is start of "bar", which is hidden editable, 
and end position is "foo", which isn't editable, to editable position but 
|DeleteSelectionCommand| checks both editability and visibility, then it gets 
null position since end point is hidden. 


BUG=339187
TEST=LayoutTests/editing/execCommand/delete-hidden-crash.html

Review URL: https://codereview.chromium.org/340713003

git-svn-id: svn://svn.chromium.org/blink/trunk@176497 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Temporarily mark non-virtual Service Worker tests as failing

This is preparation for removing the --enable-service-worker flag and
removing the virtual/serviceworker test suite.

BUG=365201

Review URL: https://codereview.chromium.org/338853006

git-svn-id: svn://svn.chromium.org/blink/trunk@176498 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Map light-source oBB-relative coordinates to the user-space of the filter

The 'fePointLight' and 'feSpotLight' light-source elements for
'fe{Diffuse,Specular}Lighting' defines positions, and in the case of
the latter a 'look-at' point (implicit direction). When an SVG filter is
declared to use primitiveUnits=objectBoundingBox, these positions/points
needs to be mapped to the user-space of the filter.
This is achieved by adding a new method resolve3dPoint() to Filter, and
perform the coordinate space mapping when creating the various
LightSources.
Open-code SVGFELightElement::findLightSource() in it's sources to avoid
passing the Filter-instance around more than necessary.

BUG=176419

Review URL: https://codereview.chromium.org/337903003

git-svn-id: svn://svn.chromium.org/blink/trunk@176499 bbb929c8-8fbe-4397-9dbb-9b2b20218538