Add support for direct DevTools protocol messaging (fixes issue #2961).

This change allows the client to directly send and receive DevTools
protocol messages (send method calls, and receive method results and
events) without requiring a DevTools front-end or remote-debugging
session.

This change includes additional supporting changes:
- Add a new CefRequestHandler::OnDocumentAvailableInMainFrame
  callback (see issue #1454).
- Add a CefParseJSON variant that accepts a UTF8-encoded buffer.
- Add a `--devtools-protocol-log-file=<path>` command-line flag for
  logging protocol messages sent to/from the DevTools front-end
  while it is displayed. This is useful for understanding existing
  DevTools protocol usage.
- Add a new "libcef_static_unittests" executable target to support
  light-weight unit tests of libcef_static internals (e.g. without
  requiring exposure via the CEF API). Files to be unittested are
  placed in the new "libcef_static_unittested" source_set which is
  then included by both the existing libcef_static library and the
  new unittests executable target.
- Linux: Remove use_bundled_fontconfig=false, which is no longer
  required and causes unittest build errors (see issue #2424).

This change also adds a cefclient demo for configuring offline mode
using the DevTools protocol (fixes issue #245). This is controlled
by the "Offline mode" context menu option and the `--offline`
command-line switch which will launch cefclient in offline mode. When
cefclient is offline all network requests will fail with
ERR_INTERNET_DISCONNECTED and navigator.onLine will return false when
called from JavaScript in any frame. This mode is per-browser so
newly created browser windows will have the default mode. Note that
configuring offline mode in this way will not update the Network tab
UI ("Throtting" option) in a displayed DevTools front-end instance.

libcef_dll/cpptoc/browser_host_cpptoc.cc

@@ -9,7 +9,7 @@
 // implementations. See the translator.README.txt file in the tools directory
 // for more information.
 //
-// $hash=a84451b4f759f2a4a0fe673d90be1fb5053bfd1a$
+// $hash=516b55b7ea53e2de2b096e85ba0eb83f2a2693f3$
 //
 
 #include "libcef_dll/cpptoc/browser_host_cpptoc.h"
@@ -18,8 +18,10 @@
 #include "libcef_dll/cpptoc/drag_data_cpptoc.h"
 #include "libcef_dll/cpptoc/extension_cpptoc.h"
 #include "libcef_dll/cpptoc/navigation_entry_cpptoc.h"
+#include "libcef_dll/cpptoc/registration_cpptoc.h"
 #include "libcef_dll/cpptoc/request_context_cpptoc.h"
 #include "libcef_dll/ctocpp/client_ctocpp.h"
+#include "libcef_dll/ctocpp/dev_tools_message_observer_ctocpp.h"
 #include "libcef_dll/ctocpp/download_image_callback_ctocpp.h"
 #include "libcef_dll/ctocpp/navigation_entry_visitor_ctocpp.h"
 #include "libcef_dll/ctocpp/pdf_print_callback_ctocpp.h"
@@ -522,6 +524,81 @@ int CEF_CALLBACK browser_host_has_dev_tools(struct _cef_browser_host_t* self) {
   return _retval;
 }
 
+int CEF_CALLBACK
+browser_host_send_dev_tools_message(struct _cef_browser_host_t* self,
+                                    const void* message,
+                                    size_t message_size) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return 0;
+  // Verify param: message; type: simple_byaddr
+  DCHECK(message);
+  if (!message)
+    return 0;
+
+  // Execute
+  bool _retval = CefBrowserHostCppToC::Get(self)->SendDevToolsMessage(
+      message, message_size);
+
+  // Return type: bool
+  return _retval;
+}
+
+int CEF_CALLBACK
+browser_host_execute_dev_tools_method(struct _cef_browser_host_t* self,
+                                      int message_id,
+                                      const cef_string_t* method,
+                                      struct _cef_dictionary_value_t* params) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return 0;
+  // Verify param: method; type: string_byref_const
+  DCHECK(method);
+  if (!method)
+    return 0;
+  // Unverified params: params
+
+  // Execute
+  int _retval = CefBrowserHostCppToC::Get(self)->ExecuteDevToolsMethod(
+      message_id, CefString(method), CefDictionaryValueCppToC::Unwrap(params));
+
+  // Return type: simple
+  return _retval;
+}
+
+struct _cef_registration_t* CEF_CALLBACK
+browser_host_add_dev_tools_message_observer(
+    struct _cef_browser_host_t* self,
+    struct _cef_dev_tools_message_observer_t* observer) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return NULL;
+  // Verify param: observer; type: refptr_diff
+  DCHECK(observer);
+  if (!observer)
+    return NULL;
+
+  // Execute
+  CefRefPtr<CefRegistration> _retval =
+      CefBrowserHostCppToC::Get(self)->AddDevToolsMessageObserver(
+          CefDevToolsMessageObserverCToCpp::Wrap(observer));
+
+  // Return type: refptr_same
+  return CefRegistrationCppToC::Wrap(_retval);
+}
+
 void CEF_CALLBACK
 browser_host_get_navigation_entries(struct _cef_browser_host_t* self,
                                     cef_navigation_entry_visitor_t* visitor,
@@ -1285,6 +1362,10 @@ CefBrowserHostCppToC::CefBrowserHostCppToC() {
   GetStruct()->show_dev_tools = browser_host_show_dev_tools;
   GetStruct()->close_dev_tools = browser_host_close_dev_tools;
   GetStruct()->has_dev_tools = browser_host_has_dev_tools;
+  GetStruct()->send_dev_tools_message = browser_host_send_dev_tools_message;
+  GetStruct()->execute_dev_tools_method = browser_host_execute_dev_tools_method;
+  GetStruct()->add_dev_tools_message_observer =
+      browser_host_add_dev_tools_message_observer;
   GetStruct()->get_navigation_entries = browser_host_get_navigation_entries;
   GetStruct()->set_mouse_cursor_change_disabled =
       browser_host_set_mouse_cursor_change_disabled;

libcef_dll/cpptoc/dev_tools_message_observer_cpptoc.cc

@@ -0,0 +1,184 @@
+// Copyright (c) 2020 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+//
+// ---------------------------------------------------------------------------
+//
+// This file was generated by the CEF translator tool. If making changes by
+// hand only do so within the body of existing method and function
+// implementations. See the translator.README.txt file in the tools directory
+// for more information.
+//
+// $hash=c4a7b4d679f1f2ed47fc31df3e2099962d5cb9d6$
+//
+
+#include "libcef_dll/cpptoc/dev_tools_message_observer_cpptoc.h"
+#include "libcef_dll/ctocpp/browser_ctocpp.h"
+#include "libcef_dll/shutdown_checker.h"
+
+namespace {
+
+// MEMBER FUNCTIONS - Body may be edited by hand.
+
+int CEF_CALLBACK dev_tools_message_observer_on_dev_tools_message(
+    struct _cef_dev_tools_message_observer_t* self,
+    cef_browser_t* browser,
+    const void* message,
+    size_t message_size) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return 0;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return 0;
+  // Verify param: message; type: simple_byaddr
+  DCHECK(message);
+  if (!message)
+    return 0;
+
+  // Execute
+  bool _retval = CefDevToolsMessageObserverCppToC::Get(self)->OnDevToolsMessage(
+      CefBrowserCToCpp::Wrap(browser), message, message_size);
+
+  // Return type: bool
+  return _retval;
+}
+
+void CEF_CALLBACK dev_tools_message_observer_on_dev_tools_method_result(
+    struct _cef_dev_tools_message_observer_t* self,
+    cef_browser_t* browser,
+    int message_id,
+    int success,
+    const void* result,
+    size_t result_size) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return;
+  // Unverified params: result
+
+  // Execute
+  CefDevToolsMessageObserverCppToC::Get(self)->OnDevToolsMethodResult(
+      CefBrowserCToCpp::Wrap(browser), message_id, success ? true : false,
+      result, result_size);
+}
+
+void CEF_CALLBACK dev_tools_message_observer_on_dev_tools_event(
+    struct _cef_dev_tools_message_observer_t* self,
+    cef_browser_t* browser,
+    const cef_string_t* method,
+    const void* params,
+    size_t params_size) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return;
+  // Verify param: method; type: string_byref_const
+  DCHECK(method);
+  if (!method)
+    return;
+  // Unverified params: params
+
+  // Execute
+  CefDevToolsMessageObserverCppToC::Get(self)->OnDevToolsEvent(
+      CefBrowserCToCpp::Wrap(browser), CefString(method), params, params_size);
+}
+
+void CEF_CALLBACK dev_tools_message_observer_on_dev_tools_agent_attached(
+    struct _cef_dev_tools_message_observer_t* self,
+    cef_browser_t* browser) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return;
+
+  // Execute
+  CefDevToolsMessageObserverCppToC::Get(self)->OnDevToolsAgentAttached(
+      CefBrowserCToCpp::Wrap(browser));
+}
+
+void CEF_CALLBACK dev_tools_message_observer_on_dev_tools_agent_detached(
+    struct _cef_dev_tools_message_observer_t* self,
+    cef_browser_t* browser) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return;
+
+  // Execute
+  CefDevToolsMessageObserverCppToC::Get(self)->OnDevToolsAgentDetached(
+      CefBrowserCToCpp::Wrap(browser));
+}
+
+}  // namespace
+
+// CONSTRUCTOR - Do not edit by hand.
+
+CefDevToolsMessageObserverCppToC::CefDevToolsMessageObserverCppToC() {
+  GetStruct()->on_dev_tools_message =
+      dev_tools_message_observer_on_dev_tools_message;
+  GetStruct()->on_dev_tools_method_result =
+      dev_tools_message_observer_on_dev_tools_method_result;
+  GetStruct()->on_dev_tools_event =
+      dev_tools_message_observer_on_dev_tools_event;
+  GetStruct()->on_dev_tools_agent_attached =
+      dev_tools_message_observer_on_dev_tools_agent_attached;
+  GetStruct()->on_dev_tools_agent_detached =
+      dev_tools_message_observer_on_dev_tools_agent_detached;
+}
+
+// DESTRUCTOR - Do not edit by hand.
+
+CefDevToolsMessageObserverCppToC::~CefDevToolsMessageObserverCppToC() {
+  shutdown_checker::AssertNotShutdown();
+}
+
+template <>
+CefRefPtr<CefDevToolsMessageObserver>
+CefCppToCRefCounted<CefDevToolsMessageObserverCppToC,
+                    CefDevToolsMessageObserver,
+                    cef_dev_tools_message_observer_t>::
+    UnwrapDerived(CefWrapperType type, cef_dev_tools_message_observer_t* s) {
+  NOTREACHED() << "Unexpected class type: " << type;
+  return nullptr;
+}
+
+template <>
+CefWrapperType
+    CefCppToCRefCounted<CefDevToolsMessageObserverCppToC,
+                        CefDevToolsMessageObserver,
+                        cef_dev_tools_message_observer_t>::kWrapperType =
+        WT_DEV_TOOLS_MESSAGE_OBSERVER;

libcef_dll/cpptoc/dev_tools_message_observer_cpptoc.h

@@ -0,0 +1,40 @@
+// Copyright (c) 2020 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+//
+// ---------------------------------------------------------------------------
+//
+// This file was generated by the CEF translator tool. If making changes by
+// hand only do so within the body of existing method and function
+// implementations. See the translator.README.txt file in the tools directory
+// for more information.
+//
+// $hash=d48f93f3817dab7daf0e30a6fa94b1a173356383$
+//
+
+#ifndef CEF_LIBCEF_DLL_CPPTOC_DEV_TOOLS_MESSAGE_OBSERVER_CPPTOC_H_
+#define CEF_LIBCEF_DLL_CPPTOC_DEV_TOOLS_MESSAGE_OBSERVER_CPPTOC_H_
+#pragma once
+
+#if !defined(WRAPPING_CEF_SHARED)
+#error This file can be included wrapper-side only
+#endif
+
+#include "include/capi/cef_browser_capi.h"
+#include "include/capi/cef_devtools_message_observer_capi.h"
+#include "include/cef_browser.h"
+#include "include/cef_devtools_message_observer.h"
+#include "libcef_dll/cpptoc/cpptoc_ref_counted.h"
+
+// Wrap a C++ class with a C structure.
+// This class may be instantiated and accessed wrapper-side only.
+class CefDevToolsMessageObserverCppToC
+    : public CefCppToCRefCounted<CefDevToolsMessageObserverCppToC,
+                                 CefDevToolsMessageObserver,
+                                 cef_dev_tools_message_observer_t> {
+ public:
+  CefDevToolsMessageObserverCppToC();
+  virtual ~CefDevToolsMessageObserverCppToC();
+};
+
+#endif  // CEF_LIBCEF_DLL_CPPTOC_DEV_TOOLS_MESSAGE_OBSERVER_CPPTOC_H_

libcef_dll/cpptoc/request_handler_cpptoc.cc

@@ -9,7 +9,7 @@
 // implementations. See the translator.README.txt file in the tools directory
 // for more information.
 //
-// $hash=68840d18a25efe4d749e480225d7ac3caacd4723$
+// $hash=716501855da0203723eb18bfb9e518c7b155f110$
 //
 
 #include "libcef_dll/cpptoc/request_handler_cpptoc.h"
@@ -396,6 +396,26 @@ void CEF_CALLBACK request_handler_on_render_process_terminated(
       CefBrowserCToCpp::Wrap(browser), status);
 }
 
+void CEF_CALLBACK request_handler_on_document_available_in_main_frame(
+    struct _cef_request_handler_t* self,
+    cef_browser_t* browser) {
+  shutdown_checker::AssertNotShutdown();
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return;
+
+  // Execute
+  CefRequestHandlerCppToC::Get(self)->OnDocumentAvailableInMainFrame(
+      CefBrowserCToCpp::Wrap(browser));
+}
+
 }  // namespace
 
 // CONSTRUCTOR - Do not edit by hand.
@@ -414,6 +434,8 @@ CefRequestHandlerCppToC::CefRequestHandlerCppToC() {
   GetStruct()->on_render_view_ready = request_handler_on_render_view_ready;
   GetStruct()->on_render_process_terminated =
       request_handler_on_render_process_terminated;
+  GetStruct()->on_document_available_in_main_frame =
+      request_handler_on_document_available_in_main_frame;
 }
 
 // DESTRUCTOR - Do not edit by hand.