Add a flag to enable remote CoreAnimation API.

A follow-on patch will switch this flag to be enabled by default.

BUG=312462
TBR=kbr
R=sky

Review URL: https://codereview.chromium.org/464063005

Cr-Commit-Position: refs/heads/master@{#289835}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@289835 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ui/base/ui_base_switches.cc b/ui/base/ui_base_switches.cc
index 9bacd0a7..eadd359 100644
--- a/ui/base/ui_base_switches.cc
+++ b/ui/base/ui_base_switches.cc
@@ -9,6 +9,10 @@
 #if defined(OS_MACOSX) && !defined(OS_IOS)
 // Disable use of CoreAnimation to draw on the Mac.
 const char kDisableCoreAnimation[] = "disable-core-animation";
+
+// Enable use of cross-process CALayers to display content directly from the
+// GPU process on Mac.
+const char kEnableRemoteCoreAnimation[] = "enable-remote-core-animation";
 #endif
 
 // Disables use of DWM composition for top level windows.