Remove the allow-displaying-mixed-content setting from Blink.

chrome/common/pref_names.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Constants for the names of various preferences, for easier changing.
 
 #ifndef CHROME_COMMON_PREF_NAMES_H_
 #define CHROME_COMMON_PREF_NAMES_H_
 
 #include <stddef.h>
@@ skipping 122 matching lines @@
 extern const char kWebKitMinimumFontSize[];
 extern const char kWebKitMinimumLogicalFontSize[];
 extern const char kWebKitJavascriptEnabled[];
 extern const char kWebKitWebSecurityEnabled[];
 extern const char kWebKitJavascriptCanOpenWindowsAutomatically[];
 extern const char kWebKitLoadsImagesAutomatically[];
 extern const char kWebKitPluginsEnabled[];
 extern const char kWebKitDomPasteEnabled[];
 extern const char kWebKitTextAreasAreResizable[];
 extern const char kWebkitTabsToLinks[];
-extern const char kWebKitAllowDisplayingInsecureContent[];
 extern const char kWebKitAllowRunningInsecureContent[];
 #if defined(OS_ANDROID)
 extern const char kWebKitFontScaleFactor[];
 extern const char kWebKitForceEnableZoom[];
 extern const char kWebKitPasswordEchoEnabled[];
 #endif
 extern const char kDataSaverEnabled[];
 extern const char kSafeBrowsingEnabled[];
 extern const char kSafeBrowsingExtendedReportingEnabled[];
 extern const char kSafeBrowsingProceedAnywayDisabled[];
@@ skipping 673 matching lines @@
 #endif
 
 extern const char kOriginTrialPublicKey[];
 extern const char kOriginTrialDisabledFeatures[];
 
 extern const char kComponentUpdatesEnabled[];
 
 }  // namespace prefs
 
 #endif  // CHROME_COMMON_PREF_NAMES_H_