Ensure that custom cursors set by windowless flash plugins get marshaled corr...

Ensure that custom cursors set by windowless flash plugins get marshaled correctly back
to the renderer and eventually to the browser. We rely on the HCURSOR getting marshaled
across on windows. However this regressed when code to validate the custom cursor info
was added in the WebCursor deserialization routines.

Fixes bug http://code.google.com/p/chromium/issues/list?cursor=39436

BUG=39436
TEST=Covered by new custom cursor deserialization unit test.


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=68759

[jam, 2010-12-09 19:03:05]

lgtm