Revert of [SVG] Promote PathOpsSVGClipping to stable.

Revert of [SVG] Promote PathOpsSVGClipping to stable. (patchset #1 id:1 of https://codereview.chromium.org/446583002/)

Reason for revert:
We've received valuable feedback from exposure to stable. Dialing back while the issues are being worked on.

Original issue's description:
> [SVG] Promote PathOpsSVGClipping to stable.
> 
> The feature has been in experimental state for more than a month with
> no known issues.
> 
> BUG=263911
> R=schenney@chromium.org, fs@opera.com, pdr@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179529

TBR=fs@opera.com,pdr@chromium.org,schenney@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=263911
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=183894

[f(malita), 2014-10-17 15:28:46]

Created Revert of [SVG] Promote PathOpsSVGClipping to stable.

[commit-bot: I haz the power, 2014-10-17 15:29:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/645023003/1

[commit-bot: I haz the power, 2014-10-17 15:29:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-10-17 15:29:58]

Failed to apply patch for Source/platform/RuntimeEnabledFeatures.in:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file Source/platform/RuntimeEnabledFeatures.in
  Hunk #1 FAILED at 97.
  1 out of 1 hunk FAILED -- saving rejects to file
Source/platform/RuntimeEnabledFeatures.in.rej

Patch:       Source/platform/RuntimeEnabledFeatures.in
Index: Source/platform/RuntimeEnabledFeatures.in
diff --git a/Source/platform/RuntimeEnabledFeatures.in
b/Source/platform/RuntimeEnabledFeatures.in
index
3332d91fb046f003f22cbc3dbecc7aab7535bd9f..ed36257399748e886664f045bd354de674065d7e
100644
--- a/Source/platform/RuntimeEnabledFeatures.in
+++ b/Source/platform/RuntimeEnabledFeatures.in
@@ -97,7 +97,7 @@
 OverlayFullscreenVideo
 PagePopup status=stable
 Path2D status=stable
-PathOpsSVGClipping status=stable
+PathOpsSVGClipping status=experimental
 PeerConnection depends_on=MediaStream, status=stable
 PreciseMemoryInfo
 PushMessaging status=experimental

[f(malita), 2014-10-17 15:32:37]

The CQ bit was checked by fmalita@chromium.org

[commit-bot: I haz the power, 2014-10-17 15:33:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/645023003/40001

[commit-bot: I haz the power, 2014-10-17 15:33:45]

Committed patchset #2 (id:40001) as 183894