Add --{enable,disable}-blink-features flags which set RuntimeEnabledFeatures.

content/public/common/content_switches.h

Index: content/public/common/content_switches.h
diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
index 916501ea4b1c180fc59bd8a97d30955cafd2f66f..f727047b99833bcae465a4fb309e5592362b38f8 100644
--- a/content/public/common/content_switches.h
+++ b/content/public/common/content_switches.h
@@ -31,6 +31,7 @@ CONTENT_EXPORT extern const char kDefaultTileWidth[];
 CONTENT_EXPORT extern const char kDefaultTileHeight[];
 CONTENT_EXPORT extern const char kDisable2dCanvasAntialiasing[];
 CONTENT_EXPORT extern const char kDisable3DAPIs[];
+CONTENT_EXPORT extern const char kDisableBlinkFeatures[];
 CONTENT_EXPORT extern const char kDisableAccelerated2dCanvas[];
 CONTENT_EXPORT extern const char kDisableAcceleratedJpegDecoding[];
 CONTENT_EXPORT extern const char kDisableAcceleratedVideoDecode[];
@@ -90,6 +91,7 @@ CONTENT_EXPORT extern const char kEnableBleedingEdgeRenderingFastPaths[];
 CONTENT_EXPORT extern const char kEnableCredentialManagerAPI[];
 CONTENT_EXPORT extern const char kEnableBeginFrameScheduling[];
 CONTENT_EXPORT extern const char kEnablePreferCompositingToLCDText[];
+CONTENT_EXPORT extern const char kEnableBlinkFeatures[];
 CONTENT_EXPORT extern const char kEnableBrowserSideNavigation[];
 CONTENT_EXPORT extern const char kEnableDeferredImageDecoding[];
 CONTENT_EXPORT extern const char kEnableDelayAgnosticAec[];