cc: Allow sending BeginMainFrame before draw or activation

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index 46f4992dd2ac4c73d598bd032a250ad55b8ae57a..43fca91cc1f7726e6bcba4f52690ae915c862426 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -15,6 +15,19 @@ const char kDisableThreadedAnimation[] = "disable-threaded-animation";
 const char kDisableCompositedAntialiasing[] =
     "disable-composited-antialiasing";
 
+// Disables sending the next BeginMainFrame before the previous commit has
+// drawn.
+const char kDisableMainFrameBeforeDraw[] = "disable-main-frame-before-draw";
+
+// Disables sending the next BeginMainFrame before the previous commit
+// activates. Overrides the kEnableMainFrameBeforeActivation flag.
+const char kDisableMainFrameBeforeActivation[] =
+    "disable-main-frame-before-activation";
+
+// Enables sending the next BeginMainFrame before the previous commit activates.
+const char kEnableMainFrameBeforeActivation[] =
+    "enable-main-frame-before-activation";
+
 const char kEnableTopControlsPositionCalculation[] =
     "enable-top-controls-position-calculation";