Revert of cc: Enable impl-side painting by default on all platforms where...

Revert of cc: Enable impl-side painting by default on all platforms where threaded compositing is used. (https://codereview.chromium.org/242803007/)

Reason for revert:
This makes DevTools unusable on Linux Aura, see crbug.com/367673.

Original issue's description:
> cc: Enable impl-side painting by default on all platforms where threaded compositing is used.
> 
> BUG=169282
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=266471

TBR=piman@chromium.org,vangelis@chromium.org,enne@chromium.org,reveman@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=169282

Review URL: https://codereview.chromium.org/259843006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266499 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/gpu/compositor_util.cc

@@ -181,7 +181,11 @@ bool IsImplSidePaintingEnabled() {
   else if (command_line.HasSwitch(switches::kEnableImplSidePainting))
     return true;
 
-  return IsThreadedCompositingEnabled();
+#if defined(OS_ANDROID)
+  return true;
+#else
+  return false;
+#endif
 }
 
 bool IsGpuRasterizationEnabled() {