DevTools: restore styles for console navigation and violation messages

DevTools prints console System-type Info-level messages only in 2 cases
- MainFrame navigations "Navigated to ..."
- Dumping size of large Common.Settings that failed to save

This CL sets text color to blue in these cases, and also sets
dark-theme violation text to original warning colors.

Screenshot: https://imgur.com/a/yaIbr

Bug: 817429
Change-Id: Id3f2c7ad16a3f02b40b4aafe93f5ca3dcf04f4b1
Reviewed-on: https://chromium-review.googlesource.com/955893Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Erik Luo <luoe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542733}

third_party/WebKit/Source/devtools/front_end/console/ConsoleViewMessage.js

@@ -1086,6 +1086,8 @@ Console.ConsoleViewMessage = class {
         break;
       case SDK.ConsoleMessage.MessageLevel.Info:
         this._element.classList.add('console-info-level');
+        if (this._message.type === SDK.ConsoleMessage.MessageType.System)
+          this._element.classList.add('console-system-type');
         break;
       case SDK.ConsoleMessage.MessageLevel.Warning:
         this._element.classList.add('console-warning-level');

third_party/WebKit/Source/devtools/front_end/console/consoleView.css

@@ -256,12 +256,17 @@
     color: red !important;
 }
 
+.console-system-type.console-info-level {
+    color: blue;
+}
+
 .-theme-with-dark-background .console-error-level .console-message-text,
 .-theme-with-dark-background .console-error-level .console-view-object-properties-section {
     color: hsl(0, 100%, 75%) !important;
 }
 
-.-theme-with-dark-background .console-verbose-level .console-message-text {
+.-theme-with-dark-background .console-verbose-level:not(.console-warning-level) .console-message-text,
+.-theme-with-dark-background .console-system-type.console-info-level {
     color: hsl(220, 100%, 65%) !important;
 }