Organize security panel main view.

Source/devtools/front_end/security/lockIcon.css

 /* Copyright (c) 2015 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.
  */
 
 .lock-icon,
 .security-property {
     background-size: cover;
     height: 16px;
     width: 16px;
 }
 
 .lock-icon-unknown {
-    background-image: url(Images/securityStateNeutral.png);
+    background-image: url(Images/securityStateNeutral.svg);
 }
 
 .lock-icon-neutral {
-    background-image: url(Images/securityStateNeutral.png);
+    background-image: url(Images/securityStateNeutral.svg);
 }
 
 .lock-icon-insecure {
-    background-image: url(Images/securityStateInsecure.png);
-}
-
-.lock-icon-warning {
-    background-image: url(Images/securityStateWarning.png);
+    background-image: url(Images/securityStateInsecure.svg);
 }
 
 .lock-icon-secure {
-    background-image: url(Images/securityStateSecure.png);
-}
-
-
-@media (-webkit-min-device-pixel-ratio: 1.5) {
-    .lock-icon-unknown {
-        background-image: url(Images/securityStateNeutral_2x.png);
-    }
-
-    .lock-icon-neutral {
-        background-image: url(Images/securityStateNeutral_2x.png);
-    }
-
-    .lock-icon-insecure {
-        background-image: url(Images/securityStateInsecure_2x.png);
-    }
-
-    .lock-icon-warning {
-        background-image: url(Images/securityStateWarning_2x.png);
-    }
-
-    .lock-icon-secure {
-        background-image: url(Images/securityStateSecure_2x.png);
-    }
+    background-image: url(Images/securityStateSecure.svg);
 }
 
 .security-property-insecure {
     background-image: url(Images/securityPropertyInsecure.svg);
 }
 
 .security-property-neutral {
     background-image: url(Images/securityPropertyWarning.svg);
 }
 
 .security-property-warning {
     background-image: url(Images/securityPropertyWarning.svg);
 }
 
 .security-property-secure {
     background-image: url(Images/securityPropertySecure.svg);
 }