Add a flag to enable remote CoreAnimation API.

ui/base/ui_base_switches.cc

Index: ui/base/ui_base_switches.cc
diff --git a/ui/base/ui_base_switches.cc b/ui/base/ui_base_switches.cc
index 9bacd0a71c2855db41efe4b66370bc8873a6123d..f7c564d7f0b2555de815f895ecab40a7f8f9692f 100644
--- a/ui/base/ui_base_switches.cc
+++ b/ui/base/ui_base_switches.cc
@@ -7,6 +7,10 @@
 namespace switches {
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
+// Enable use of cross-process CALayers to display content directly from the
+// GPU process on Mac.
+const char kEnableRemoteCoreAnimation[] = "enable-remote-core-animation";
+
 // Disable use of CoreAnimation to draw on the Mac.
 const char kDisableCoreAnimation[] = "disable-core-animation";
 #endif