Roll src/third_party/WebKit 52fee73:5210034 (svn 195486:195493)

Summary of changes available at:
https://chromium.googlesource.com/chromium/blink/+log/52fee73..5210034

TBR=kbr@chromium.org,hiroshige@chromium.org

Review URL: https://codereview.chromium.org/1144663004

Cr-Commit-Position: refs/heads/master@{#330470}

DEPS

@@ -34,7 +34,7 @@ vars = {
   'llvm_url': 'http://src.chromium.org/llvm-project',
   'llvm_git': 'https://llvm.googlesource.com',
   'webkit_trunk': 'http://src.chromium.org/blink/trunk',
-  'webkit_revision': '52fee7382c1f0d635c993f6ac46b1f15fb202302', # from svn revision 195486
+  'webkit_revision': '52100348948ad90e4bce5256383fbe19eca64554', # from svn revision 195493
   'chromium_git': 'https://chromium.googlesource.com',
   'chromiumos_git': 'https://chromium.googlesource.com/chromiumos',
   'pdfium_git': 'https://pdfium.googlesource.com',