Remove the ENABLE_IFRAME_SEAMLESS compile-time flag.

Source/WebCore/bindings/generic/RuntimeEnabledFeatures.h

Index: Source/WebCore/bindings/generic/RuntimeEnabledFeatures.h
diff --git a/Source/WebCore/bindings/generic/RuntimeEnabledFeatures.h b/Source/WebCore/bindings/generic/RuntimeEnabledFeatures.h
index b4e7775e6134f3c874497fc0eef4f836150f63ee..ae7bfa6777e854eee941ef05659ba0ae5b8151f9 100644
--- a/Source/WebCore/bindings/generic/RuntimeEnabledFeatures.h
+++ b/Source/WebCore/bindings/generic/RuntimeEnabledFeatures.h
@@ -289,10 +289,8 @@ public:
     static void setExperimentalContentSecurityPolicyFeaturesEnabled(bool isEnabled) { areExperimentalContentSecurityPolicyFeaturesEnabled = isEnabled; }
 #endif
 
-#if ENABLE(IFRAME_SEAMLESS)
     static bool seamlessIFramesEnabled() { return areSeamlessIFramesEnabled; }
     static void setSeamlessIFramesEnabled(bool isEnabled) { areSeamlessIFramesEnabled = isEnabled; }
-#endif
 
     static bool langAttributeAwareFormControlUIEnabled() { return isLangAttributeAwareFormControlUIEnabled; }
     // The lang attribute support is incomplete and should only be turned on for tests.
@@ -418,9 +416,7 @@ private:
     static bool areExperimentalContentSecurityPolicyFeaturesEnabled;
 #endif
 
-#if ENABLE(IFRAME_SEAMLESS)
     static bool areSeamlessIFramesEnabled;
-#endif
 
 #if ENABLE(FONT_LOAD_EVENTS)
     static bool isFontLoadEventsEnabled;