Enable V8 sandbox by default (fixes #3332)

When the V8 sandbox is enabled, ArrayBuffer backing stores must be
allocated inside the sandbox address space. This change introduces a new
CefV8Value::CreateArrayBufferWithCopy method that copies the memory
contents into the sandbox address space.

Enabling the V8 sandbox can have a performance impact, especially when
passing large ArrayBuffers from C++ code to the JS side. We have therefore
retained the old CefV8Value::CreateArrayBuffer method that references
external memory. However, this method can only be used if the V8 sandbox is
disabled at CEF/Chromium build time.

To disable the V8 sandbox add `v8_enable_sandbox=false` to
`GN_DEFINES` when building CEF/Chromium.

libcef_dll/cpptoc/v8value_cpptoc.cc

@@ -9,7 +9,7 @@
 // implementations. See the translator.README.txt file in the tools directory
 // for more information.
 //
-// $hash=c59808566c2a9f2d204b6724bb5a905aeb0e7620$
+// $hash=befb2f29af8a0e8eabf745fad126ebad5a741c74$
 //
 
 #include "libcef_dll/cpptoc/v8value_cpptoc.h"
@@ -155,6 +155,21 @@ CEF_EXPORT cef_v8value_t* cef_v8value_create_array_buffer(
   return CefV8ValueCppToC::Wrap(_retval);
 }
 
+CEF_EXPORT cef_v8value_t* cef_v8value_create_array_buffer_with_copy(
+    void* buffer,
+    size_t length) {
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  // Unverified params: buffer
+
+  // Execute
+  CefRefPtr<CefV8Value> _retval =
+      CefV8Value::CreateArrayBufferWithCopy(buffer, length);
+
+  // Return type: refptr_same
+  return CefV8ValueCppToC::Wrap(_retval);
+}
+
 CEF_EXPORT cef_v8value_t* cef_v8value_create_function(
     const cef_string_t* name,
     cef_v8handler_t* handler) {