resubmit https://code.google.com/p/skia/source/detail?r=7883 (in the meantime we

resubmit https://code.google.com/p/skia/source/detail?r=7883 (in the meantime we
added capability to collect minidump and callstack if buildbot fails with heap
coruption in windows, and a NPE bug was fixed in SkPDFDocument, when document was destroyed without ever beeing used and a field was NULL + a few minor conflicts have been resolved)

git-svn-id: http://skia.googlecode.com/svn/trunk@8487 2bbb7eff-a529-9590-31e7-b0007b416f81