Add a SessionPreferences to manage session related data

By design the BrowserClient should not be aware of the api:: classes.

atom/browser/session_preferences.cc

@@ -0,0 +1,61 @@
+// Copyright (c) 2017 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/session_preferences.h"
+
+#include "atom/common/options_switches.h"
+#include "base/command_line.h"
+#include "base/memory/ptr_util.h"
+
+namespace atom {
+
+namespace {
+
+#if defined(OS_WIN)
+const base::FilePath::CharType kPathDelimiter = FILE_PATH_LITERAL(';');
+#else
+const base::FilePath::CharType kPathDelimiter = FILE_PATH_LITERAL(':');
+#endif
+
+}  // namespace
+
+// static
+int SessionPreferences::kLocatorKey = 0;
+
+SessionPreferences::SessionPreferences(content::BrowserContext* context) {
+  context->SetUserData(&kLocatorKey, base::WrapUnique(this));
+}
+
+SessionPreferences::~SessionPreferences() {
+}
+
+// static
+SessionPreferences* SessionPreferences::FromBrowserContext(
+    content::BrowserContext* context) {
+  return static_cast<SessionPreferences*>(context->GetUserData(&kLocatorKey));
+}
+
+// static
+void SessionPreferences::AppendExtraCommandLineSwitches(
+    content::BrowserContext* context, base::CommandLine* command_line) {
+  SessionPreferences* self = FromBrowserContext(context);
+  if (!self)
+    return;
+
+  base::FilePath::StringType preloads;
+  for (const auto& preload : self->preloads()) {
+    if (!base::FilePath(preload).IsAbsolute()) {
+      LOG(ERROR) << "preload script must have absolute path: " << preload;
+      continue;
+    }
+    if (preloads.empty())
+      preloads = preload;
+    else
+      preloads += kPathDelimiter + preload;
+  }
+  if (!preloads.empty())
+    command_line->AppendSwitchNative(switches::kPreloadScripts, preloads);
+}
+
+}  // namespace atom