Remove the ENABLE_IFRAME_SEAMLESS compile-time flag.

Source/WebKit/chromium/src/WebRuntimeFeatures.cpp

Index: Source/WebKit/chromium/src/WebRuntimeFeatures.cpp
diff --git a/Source/WebKit/chromium/src/WebRuntimeFeatures.cpp b/Source/WebKit/chromium/src/WebRuntimeFeatures.cpp
index 6fe441354a306a63fa83b04b14967b632890b06e..4addb0bd692d5667c25b8e9426471074f6ee2a4e 100644
--- a/Source/WebKit/chromium/src/WebRuntimeFeatures.cpp
+++ b/Source/WebKit/chromium/src/WebRuntimeFeatures.cpp
@@ -664,20 +664,12 @@ bool WebRuntimeFeatures::isExperimentalContentSecurityPolicyFeaturesEnabled()
 
 void WebRuntimeFeatures::enableSeamlessIFrames(bool enable)
 {
-#if ENABLE(IFRAME_SEAMLESS)
     return RuntimeEnabledFeatures::setSeamlessIFramesEnabled(enable);
-#else
-    UNUSED_PARAM(enable);
-#endif
 }
 
 bool WebRuntimeFeatures::areSeamlessIFramesEnabled()
 {
-#if ENABLE(IFRAME_SEAMLESS)
     return RuntimeEnabledFeatures::seamlessIFramesEnabled();
-#else
-    return false;
-#endif
 }
 
 void WebRuntimeFeatures::enableCanvasPath(bool enable)