Remove the usage of BrowserThread::FILE in the shell_integration* files

chrome/browser/shell_integration_linux.cc

Index: chrome/browser/shell_integration_linux.cc
diff --git a/chrome/browser/shell_integration_linux.cc b/chrome/browser/shell_integration_linux.cc
index f34c9ffb10a1225ca03507cac17b2233529bc84f..a9a1e98960cdf6467dfef7a5934294e77ecf7b96 100644
--- a/chrome/browser/shell_integration_linux.cc
+++ b/chrome/browser/shell_integration_linux.cc
@@ -50,13 +50,10 @@
 #include "chrome/common/features.h"
 #include "chrome/grit/chrome_unscaled_resources.h"
 #include "components/version_info/version_info.h"
-#include "content/public/browser/browser_thread.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image_family.h"
 #include "url/gurl.h"
 
-using content::BrowserThread;
-
 namespace shell_integration {
 
 namespace {
@@ -565,13 +562,13 @@ base::FilePath GetChromeExePath() {
 }  // namespace
 
 base::FilePath GetDataWriteLocation(base::Environment* env) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   return base::nix::GetXDGDirectory(env, "XDG_DATA_HOME", ".local/share");
 }
 
 std::vector<base::FilePath> GetDataSearchLocations(base::Environment* env) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   std::vector<base::FilePath> search_paths;
   base::FilePath write_location = GetDataWriteLocation(env);
@@ -682,7 +679,7 @@ web_app::ShortcutLocations GetExistingShortcutLocations(
     const base::FilePath& profile_path,
     const std::string& extension_id,
     const base::FilePath& desktop_path) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   base::FilePath shortcut_filename = GetExtensionShortcutFilename(
       profile_path, extension_id);
@@ -713,7 +710,7 @@ web_app::ShortcutLocations GetExistingShortcutLocations(
 bool GetExistingShortcutContents(base::Environment* env,
                                  const base::FilePath& desktop_filename,
                                  std::string* output) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   std::vector<base::FilePath> search_paths = GetDataSearchLocations(env);
 
@@ -774,7 +771,7 @@ base::FilePath GetExtensionShortcutFilename(const base::FilePath& profile_path,
 std::vector<base::FilePath> GetExistingProfileShortcutFilenames(
     const base::FilePath& profile_path,
     const base::FilePath& directory) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   // Use a prefix, because xdg-desktop-menu requires it.
   std::string prefix(chrome::kBrowserProcessExecutableName);
@@ -939,7 +936,7 @@ std::string GetDirectoryFileContents(const base::string16& title,
 bool CreateDesktopShortcut(
     const web_app::ShortcutInfo& shortcut_info,
     const web_app::ShortcutLocations& creation_locations) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   base::FilePath shortcut_filename;
   if (!shortcut_info.extension_id.empty()) {
@@ -1032,7 +1029,7 @@ bool CreateDesktopShortcut(
 bool CreateAppListDesktopShortcut(
     const std::string& wm_class,
     const std::string& title) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   base::FilePath desktop_name(kAppListDesktopName);
   base::FilePath shortcut_filename = desktop_name.AddExtension("desktop");
@@ -1072,7 +1069,7 @@ bool CreateAppListDesktopShortcut(
 
 void DeleteDesktopShortcuts(const base::FilePath& profile_path,
                             const std::string& extension_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   base::FilePath shortcut_filename = GetExtensionShortcutFilename(
       profile_path, extension_id);
@@ -1088,7 +1085,7 @@ void DeleteDesktopShortcuts(const base::FilePath& profile_path,
 }
 
 void DeleteAllDesktopShortcuts(const base::FilePath& profile_path) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   std::unique_ptr<base::Environment> env(base::Environment::Create());