diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 75e04bcbd12853..e1d92c6eb3f54b 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -998,7 +998,6 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kDisableUniversalAcceleratedOverflowScroll,
     switches::kDisableUnprefixedMediaSource,
     switches::kDisableVp8AlphaPlayback,
-    switches::kDisableWebAnimationsCSS,
     switches::kDisableWebKitMediaSource,
     switches::kDomAutomationController,
     switches::kEnableAcceleratedFixedRootBackground,
@@ -1052,7 +1051,6 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableViewportMeta,
     switches::kMainFrameResizesAreOrientationChanges,
     switches::kEnableVtune,
-    switches::kEnableWebAnimationsCSS,
     switches::kEnableWebAnimationsSVG,
     switches::kEnableWebGLDraftExtensions,
     switches::kEnableWebMIDI,
diff --git a/content/child/runtime_features.cc b/content/child/runtime_features.cc
index 9f1bb73febb0af..76c680c5566e49 100644
--- a/content/child/runtime_features.cc
+++ b/content/child/runtime_features.cc
@@ -123,13 +123,6 @@ void SetRuntimeFeaturesDefaultsAndUpdateFromArgs(
   if (command_line.HasSwitch(switches::kDisablePrefixedEncryptedMedia))
     WebRuntimeFeatures::enablePrefixedEncryptedMedia(false);
 
-  // FIXME: Remove the enable switch once Web Animations CSS is enabled by
-  // default in Blink.
-  if (command_line.HasSwitch(switches::kEnableWebAnimationsCSS))
-    WebRuntimeFeatures::enableWebAnimationsCSS(true);
-  else if (command_line.HasSwitch(switches::kDisableWebAnimationsCSS))
-    WebRuntimeFeatures::enableWebAnimationsCSS(false);
-
   if (command_line.HasSwitch(switches::kEnableWebAnimationsSVG))
     WebRuntimeFeatures::enableWebAnimationsSVG(true);
 
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 8167f967d92342..b89bbba2dca31b 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -317,9 +317,6 @@ const char kDisableUniversalAcceleratedOverflowScroll[] =
 // Disables unprefixed Media Source API (i.e., the MediaSource object).
 const char kDisableUnprefixedMediaSource[]  = "disable-unprefixed-media-source";
 
-// Disable CSS Transitions / Animations on the Web Animations model.
-const char kDisableWebAnimationsCSS[]        = "disable-web-animations-css";
-
 // Disables prefixed Media Source API (i.e., the WebKitMediaSource object).
 const char kDisableWebKitMediaSource[]      = "disable-webkit-media-source";
 
@@ -600,9 +597,6 @@ const char kEnableVisualWordMovement[]      = "enable-visual-word-movement";
 // Enable the Vtune profiler support.
 const char kEnableVtune[]                   = "enable-vtune-support";
 
-// Enable CSS Transitions / Animations on the Web Animations model.
-const char kEnableWebAnimationsCSS[]        = "enable-web-animations-css";
-
 // Enable SVG Animations on the Web Animations model.
 const char kEnableWebAnimationsSVG[]        = "enable-web-animations-svg";
 
diff --git a/content/public/common/content_switches.h b/content/public/common/content_switches.h
index 8b18c79dec2ab9..9025434c632b30 100644
--- a/content/public/common/content_switches.h
+++ b/content/public/common/content_switches.h
@@ -102,7 +102,6 @@ CONTENT_EXPORT extern const char kDisableThreadedCompositing[];
 CONTENT_EXPORT extern const char kDisableThreadedHTMLParser[];
 CONTENT_EXPORT extern const char kDisableUniversalAcceleratedOverflowScroll[];
 CONTENT_EXPORT extern const char kDisableUnprefixedMediaSource[];
-extern const char kDisableWebAnimationsCSS[];
 CONTENT_EXPORT extern const char kDisableWebKitMediaSource[];
 CONTENT_EXPORT extern const char kDisableWebSecurity[];
 extern const char kDisableXSLT[];
@@ -175,8 +174,6 @@ CONTENT_EXPORT extern const char kEnableViewportMeta[];
 CONTENT_EXPORT extern const char kMainFrameResizesAreOrientationChanges[];
 extern const char kEnableVisualWordMovement[];
 CONTENT_EXPORT extern const char kEnableVtune[];
-// FIXME: Remove this once Web Animations CSS is enabled by default in Blink.
-extern const char kEnableWebAnimationsCSS[];
 extern const char kEnableWebAnimationsSVG[];
 CONTENT_EXPORT extern const char kEnableWebGLDraftExtensions[];
 CONTENT_EXPORT extern const char kEnableWebMIDI[];