Roll src/third_party/skia/ cbecb082d..4c6e47a8a (4 commits).

https://chromium.googlesource.com/skia.git/+log/cbecb082d15d..4c6e47a8a827

$ git log cbecb082d..4c6e47a8a --date=short --no-merges --format='%ad %ae %s'
2016-07-22 jvanverth Recycle small uniform buffers.
2016-07-22 brianosman Connect dst color space in a few places (removing TODOs)
2016-07-22 mtklein Revert of Add SkRasterPipeline blitter. (patchset #18 id:340001 of https://codereview.chromium.org/2146413002/ )
2016-07-22 vjiaoblack Creating framework for drawShadowedPicture GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2146073003

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

Review-Url: https://codereview.chromium.org/2171423002
Cr-Commit-Position: refs/heads/master@{#407222}

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': 'cbecb082d15da3c9cc5ac7192b243fd26dc29a57',
+  'skia_revision': '4c6e47a8a827077e36fa5feb4ab5ac7435d8276b',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.