telemetry: add smoothness.*.key_silk_cases benchmarks

cc/base/switches.h

Index: cc/base/switches.h
diff --git a/cc/base/switches.h b/cc/base/switches.h
index 476457fe72a1518b00c693a518e52f85034f549c..a8c061dc2dd38c64b8f8dcd21aeae5bd67f7ad33 100644
--- a/cc/base/switches.h
+++ b/cc/base/switches.h
@@ -18,6 +18,7 @@ namespace switches {
 // Switches for the renderer compositor only.
 CC_EXPORT extern const char kBackgroundColorInsteadOfCheckerboard[];
 CC_EXPORT extern const char kDisableLCDText[];
+CC_EXPORT extern const char kDisableGPURasterization[];
 CC_EXPORT extern const char kDisableImplSidePainting[];
 CC_EXPORT extern const char kDisableThreadedAnimation[];
 CC_EXPORT extern const char kDisableCompositedAntialiasing[];
@@ -73,6 +74,7 @@ CC_EXPORT extern const char kCCLayerTreeTestNoTimeout[];
 CC_EXPORT extern const char kCCRebaselinePixeltests[];
 
 CC_EXPORT bool IsLCDTextEnabled();
+CC_EXPORT bool IsGpuRasterizationEnabled();
 CC_EXPORT bool IsImplSidePaintingEnabled();
 CC_EXPORT bool IsMapImageEnabled();