Roll src/third_party/pdfium/ 05e016984..708ef623c (1 commit).

https://pdfium.googlesource.com/pdfium.git/+log/05e016984447..708ef623c2e9

$ git log 05e016984..708ef623c --date=short --no-merges --format='%ad %ae %s'
2016-11-29 npm Do not clone in CPDF_ImageCacheEntry::GetCachedBitmap

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls

TBR=dsinclair@chromium.org

Review-Url: https://codereview.chromium.org/2538813002
Cr-Commit-Position: refs/heads/master@{#435058}

DEPS

@@ -64,7 +64,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.
-  'pdfium_revision': '05e01698444726fae302cd335fa4880932d7c543',
+  'pdfium_revision': '708ef623c2e989a9ad909bf0c94a7dff89694412',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling openmax_dl
   # and whatever else without interference from each other.