Roll src/third_party/skia/ 4c6e47a8a..f14916935 (4 commits).

https://chromium.googlesource.com/skia.git/+log/4c6e47a8a827..f1491693527a

$ git log 4c6e47a8a..f14916935 --date=short --no-merges --format='%ad %ae %s'
2016-07-22 bungeman Correct advances for 'monospace' fonts in PDF.
2016-07-22 mtklein Add SkRasterPipeline blitter.
2016-07-22 brianosman Bundle SkShader::asFragmentProcessor arguments in a struct
2016-07-22 caryclark limit number of searched roots

BUG=630649

CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_blink_rel
TBR=jcgregorio@google.com

Review-Url: https://codereview.chromium.org/2180483002
Cr-Commit-Position: refs/heads/master@{#407252}

DEPS

@@ -36,7 +36,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and whatever else without interference from each other.
-  'skia_revision': '4c6e47a8a827077e36fa5feb4ab5ac7435d8276b',
+  'skia_revision': 'f1491693527a70919de5d624a049cae38384474e',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.