Add initial chrome runtime support (see issue #2969)

Running `cefsimple --enable-chrome-runtime` will create and run a
Chrome browser window using the CEF app methods, and call
CefApp::OnContextInitialized as expected. CEF task methods also
work as expected in the main process. No browser-related methods or
callbacks are currently supported for the Chrome window, and the
application will exit when the last Chrome window closes.

The Chrome runtime requires resources.pak, chrome_100_percent.pak
and chrome_200_percent.pak files which were not previously built
with CEF. It shares the existing locales pak files which have been
updated to include additional Chrome-specific strings.

On Linux, the Chrome runtime requires GTK so use_gtk=true must be
specified via GN_DEFINES when building.

This change also refactors the CEF runtime, which can be tested in
the various supported modes by running:
$ cefclient
$ cefclient --multi-threaded-message-loop
$ cefclient --external-message-pump

patch/patches/chrome_runtime.patch

@@ -0,0 +1,48 @@
+diff --git chrome/browser/chrome_browser_main.cc chrome/browser/chrome_browser_main.cc
+index c06585b15b8f..b5ed3518c0fd 100644
+--- chrome/browser/chrome_browser_main.cc
++++ chrome/browser/chrome_browser_main.cc
+@@ -49,6 +49,7 @@
+ #include "build/branding_buildflags.h"
+ #include "build/build_config.h"
+ #include "cc/base/switches.h"
++#include "cef/libcef/features/chrome_cef.h"
+ #include "chrome/browser/about_flags.h"
+ #include "chrome/browser/active_use_util.h"
+ #include "chrome/browser/after_startup_task_utils.h"
+@@ -885,8 +886,10 @@ int ChromeBrowserMainParts::PreCreateThreadsImpl() {
+ #if !defined(OS_ANDROID)
+   // Create the RunLoop for MainMessageLoopRun() to use, and pass a copy of
+   // its QuitClosure to the BrowserProcessImpl to call when it is time to exit.
++  // CEF with the Chrome runtime will create and manage its own RunLoop.
+   DCHECK(!g_run_loop);
+-  g_run_loop = new base::RunLoop;
++  if (!cef::IsChromeRuntimeEnabled())
++    g_run_loop = new base::RunLoop;
+ 
+   // These members must be initialized before returning from this function.
+   // Android doesn't use StartupBrowserCreator.
+@@ -1613,7 +1616,9 @@ int ChromeBrowserMainParts::PreMainMessageLoopRunImpl() {
+ #endif  // defined(OS_MACOSX)
+ 
+     // Transfer ownership of the browser's lifetime to the BrowserProcess.
+-    browser_process_->SetQuitClosure(g_run_loop->QuitWhenIdleClosure());
++    // CEF with the Chrome runtime will create and manage its own RunLoop.
++    if (g_run_loop)
++      browser_process_->SetQuitClosure(g_run_loop->QuitWhenIdleClosure());
+     DCHECK(!run_message_loop_);
+     run_message_loop_ = true;
+   }
+diff --git ui/gtk/select_file_dialog_impl_kde.cc ui/gtk/select_file_dialog_impl_kde.cc
+index f09501d6cd8e..edfc2a4c9bb5 100644
+--- ui/gtk/select_file_dialog_impl_kde.cc
++++ ui/gtk/select_file_dialog_impl_kde.cc
+@@ -6,6 +6,8 @@
+ #include <gtk/gtk.h>
+ #include <stddef.h>
+ 
++#undef Success
++
+ #include <memory>
+ #include <set>
+ 

patch/patches/linux_chrome_page_info_1099927.patch

@@ -0,0 +1,14 @@
+diff --git chrome/browser/ui/page_info/chrome_page_info_client.cc chrome/browser/ui/page_info/chrome_page_info_client.cc
+index e2972da9e548..2f356616ed97 100644
+--- chrome/browser/ui/page_info/chrome_page_info_client.cc
++++ chrome/browser/ui/page_info/chrome_page_info_client.cc
+@@ -17,5 +17,9 @@ std::unique_ptr<PageInfoDelegate> ChromePageInfoClient::CreatePageInfoDelegate(
+ }
+ 
+ int ChromePageInfoClient::GetJavaResourceId(int native_resource_id) {
++#if defined(OS_ANDROID)
+   return ResourceMapper::MapToJavaDrawableId(native_resource_id);
++#else
++  return 0;
++#endif
+ }

patch/patches/services_network_2622.patch

@@ -1,16 +1,16 @@
 diff --git chrome/browser/net/profile_network_context_service.cc chrome/browser/net/profile_network_context_service.cc
-index 75a5ee192358..bc97cbf684c0 100644
+index 75a5ee192358..379e0bdd11b1 100644
 --- chrome/browser/net/profile_network_context_service.cc
 +++ chrome/browser/net/profile_network_context_service.cc
 @@ -18,6 +18,7 @@
  #include "base/strings/string_split.h"
  #include "base/task/post_task.h"
  #include "base/task/thread_pool.h"
-+#include "cef/libcef/features/features.h"
++#include "cef/libcef/features/chrome_cef.h"
  #include "chrome/browser/browser_process.h"
  #include "chrome/browser/content_settings/cookie_settings_factory.h"
  #include "chrome/browser/content_settings/host_content_settings_map_factory.h"
-@@ -661,9 +662,22 @@ void ProfileNetworkContextService::ConfigureNetworkContextParamsInternal(
+@@ -661,9 +662,23 @@ void ProfileNetworkContextService::ConfigureNetworkContextParamsInternal(
    network_context_params->cookie_manager_params =
        CreateCookieManagerParams(profile_, *cookie_settings_);
  
@@ -18,8 +18,8 @@ index 75a5ee192358..bc97cbf684c0 100644
 +
    // Configure on-disk storage for non-OTR profiles. OTR profiles just use
    // default behavior (in memory storage, default sizes).
-   if (!in_memory) {
-+#if BUILDFLAG(ENABLE_CEF)
+-  if (!in_memory) {
++  if (!in_memory && cef::IsCefRuntimeEnabled()) {
 +    PrefService* prefs = profile_->GetPrefs();
 +    // Configure the HTTP cache path and size.
 +    const base::FilePath& base_cache_path =
@@ -29,18 +29,22 @@ index 75a5ee192358..bc97cbf684c0 100644
 +        base_cache_path.Append(chrome::kCacheDirname);
 +    network_context_params->http_cache_max_size =
 +        prefs->GetInteger(prefs::kDiskCacheSize);
-+#else
++  }
++
++  if (!in_memory && !cef::IsCefRuntimeEnabled()) {
      PrefService* local_state = g_browser_process->local_state();
      // Configure the HTTP cache path and size.
      base::FilePath base_cache_path;
-@@ -676,6 +690,7 @@ void ProfileNetworkContextService::ConfigureNetworkContextParamsInternal(
+@@ -676,7 +691,9 @@ void ProfileNetworkContextService::ConfigureNetworkContextParamsInternal(
          base_cache_path.Append(chrome::kCacheDirname);
      network_context_params->http_cache_max_size =
          local_state->GetInteger(prefs::kDiskCacheSize);
-+#endif
++  }
  
++  if (!in_memory) {
      // Currently this just contains HttpServerProperties, but that will likely
      // change.
+     network_context_params->http_server_properties_path =
 diff --git chrome/browser/profiles/profile.h chrome/browser/profiles/profile.h
 index a48ead96b3f7..967a5975c330 100644
 --- chrome/browser/profiles/profile.h