Update to Chromium version 86.0.4240.0 (#800218)

- CefURLRequest::Create is no longer supported in the renderer process
  (see https://crbug.com/891872). Use CefFrame::CreateURLRequest instead.
- Mac platform definitions have been changed from `MACOSX` to `MAC`
  (see https://crbug.com/1105907) and related CMake macro names have
  been updated. The old `OS_MACOSX` define is still set in code and CMake
  for backwards compatibility.
- Linux ARM build is currently broken (see https://crbug.com/1123214).

libcef/browser/devtools/devtools_frontend.cc

@@ -25,6 +25,7 @@
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/task/post_task.h"
@@ -538,7 +539,7 @@ void CefDevToolsFrontend::DispatchProtocolMessage(
   if (ProtocolLoggingEnabled()) {
     // Quick check to avoid parsing the JSON object. Events begin with a
     // "method" value whereas method results begin with an "id" value.
-    LogProtocolMessage(str_message.starts_with("{\"method\":")
+    LogProtocolMessage(base::StartsWith(str_message, "{\"method\":")
                            ? ProtocolMessageType::EVENT
                            : ProtocolMessageType::RESULT,
                        str_message);