cc: Allow sending BeginMainFrame before draw or activation

cc/base/switches.h

Index: cc/base/switches.h
diff --git a/cc/base/switches.h b/cc/base/switches.h
index 689f0e99b6ee286f0bac24ebea9043b724df09a1..1c949c6194f67aec7a6a4141598cc8dac06b9aed 100644
--- a/cc/base/switches.h
+++ b/cc/base/switches.h
@@ -24,6 +24,10 @@ CC_EXPORT extern const char kDisableThreadedAnimation[];
 CC_EXPORT extern const char kDisableCompositedAntialiasing[];
 CC_EXPORT extern const char kEnableLCDText[];
 CC_EXPORT extern const char kEnableImplSidePainting[];
+CC_EXPORT extern const char kDisableStartCommitBeforeDraw[];
+CC_EXPORT extern const char kEnableStartCommitBeforeDraw[];
+CC_EXPORT extern const char kDisableStartCommitBeforeActivate[];
+CC_EXPORT extern const char kEnableStartCommitBeforeActivate[];
 CC_EXPORT extern const char kEnableTopControlsPositionCalculation[];
 CC_EXPORT extern const char kEnableGPURasterization[];
 CC_EXPORT extern const char kJankInsteadOfCheckerboard[];
@@ -72,6 +76,8 @@ CC_EXPORT extern const char kCCRebaselinePixeltests[];
 
 CC_EXPORT bool IsLCDTextEnabled();
 CC_EXPORT bool IsGpuRasterizationEnabled();
+CC_EXPORT bool IsStartCommitBeforeDrawEnabled();
+CC_EXPORT bool IsStartCommitBeforeActivateEnabled();
 CC_EXPORT bool IsImplSidePaintingEnabled();
 CC_EXPORT bool IsMapImageEnabled();