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

chrome/browser/shell_integration_win.cc

Index: chrome/browser/shell_integration_win.cc
diff --git a/chrome/browser/shell_integration_win.cc b/chrome/browser/shell_integration_win.cc
index 06dbc42d025ac612636b61e19ce233ebdeec3f5f..c8fc1ac86bd11b43b26bea15402ef5ec15fdea61 100644
--- a/chrome/browser/shell_integration_win.cc
+++ b/chrome/browser/shell_integration_win.cc
@@ -32,6 +32,7 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "base/win/registry.h"
@@ -54,12 +55,9 @@
 #include "chrome/installer/util/scoped_user_protocol_entry.h"
 #include "chrome/installer/util/shell_util.h"
 #include "components/variations/variations_associated_data.h"
-#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/utility_process_mojo_client.h"
 #include "ui/base/l10n/l10n_util.h"
 
-using content::BrowserThread;
-
 namespace shell_integration {
 
 namespace {
@@ -150,8 +148,7 @@ base::string16 GetExpectedAppId(const base::CommandLine& command_line,
 }
 
 void MigrateTaskbarPinsCallback() {
-  // This should run on the file thread.
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   // Get full path of chrome.
   base::FilePath chrome_exe;
@@ -328,7 +325,7 @@ class OpenSystemSettingsHelper {
   // watched. The array must contain at least one element.
   static void Begin(const wchar_t* const protocols[],
                     const base::Closure& on_finished_callback) {
-    DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+    base::ThreadRestrictions::AssertIOAllowed();
 
     delete instance_;
     instance_ = new OpenSystemSettingsHelper(protocols, on_finished_callback);
@@ -364,13 +361,16 @@ class OpenSystemSettingsHelper {
                    weak_ptr_factory_.GetWeakPtr(), ConcludeReason::TIMEOUT));
   }
 
+  ~OpenSystemSettingsHelper() {
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+  }
+
   // Called when a change is detected on one of the registry keys being watched.
   // Note: All types of modification to the registry key will trigger this
   //       function even if the value change is the only one that matters. This
   //       is good enough for now.
   void OnRegistryKeyChanged() {
-    DCHECK_CURRENTLY_ON(BrowserThread::FILE);
-
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
     // Make sure all the registry watchers have fired.
     if (--registry_watcher_count_ == 0) {
       UMA_HISTOGRAM_MEDIUM_TIMES(
@@ -385,7 +385,7 @@ class OpenSystemSettingsHelper {
   // |on_finished_callback_| and then dispose of this class instance to make
   // sure the callback won't get called subsequently.
   void ConcludeInteraction(ConcludeReason conclude_reason) {
-    DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
     UMA_HISTOGRAM_ENUMERATION(
         "DefaultBrowser.SettingsInteraction.ConcludeReason", conclude_reason,
@@ -398,6 +398,8 @@ class OpenSystemSettingsHelper {
   // Helper function to create a registry watcher for a given |key_path|. Do
   // nothing on initialization failure.
   void AddRegistryKeyWatcher(const wchar_t* key_path) {
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
     auto reg_key = base::MakeUnique<base::win::RegKey>(HKEY_CURRENT_USER,
                                                        key_path, KEY_NOTIFY);
 
@@ -433,6 +435,8 @@ class OpenSystemSettingsHelper {
   // Records the time it takes for the final registry watcher to get signaled.
   base::TimeTicks start_time_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   // Weak ptrs are used to bind this class to the callbacks of the timer and the
   // registry watcher. This makes it possible to self-delete after one of the
   // callbacks is executed to cancel the remaining ones.
@@ -464,6 +468,8 @@ class IsPinnedToTaskbarHelper {
   ErrorCallback error_callback_;
   ResultCallback result_callback_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(IsPinnedToTaskbarHelper);
 };
 
@@ -497,6 +503,8 @@ IsPinnedToTaskbarHelper::IsPinnedToTaskbarHelper(
 }
 
 void IsPinnedToTaskbarHelper::OnConnectionError() {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
   error_callback_.Run();
   delete this;
 }
@@ -504,6 +512,8 @@ void IsPinnedToTaskbarHelper::OnConnectionError() {
 void IsPinnedToTaskbarHelper::OnIsPinnedToTaskbarResult(
     bool succeeded,
     bool is_pinned_to_taskbar) {
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+
   result_callback_.Run(succeeded, is_pinned_to_taskbar);
   delete this;
 }
@@ -511,6 +521,8 @@ void IsPinnedToTaskbarHelper::OnIsPinnedToTaskbarResult(
 }  // namespace
 
 bool SetAsDefaultBrowser() {
+  base::ThreadRestrictions::AssertIOAllowed();
+
   base::FilePath chrome_exe;
   if (!PathService::Get(base::FILE_EXE, &chrome_exe)) {
     LOG(ERROR) << "Error getting app exe path";
@@ -530,6 +542,8 @@ bool SetAsDefaultBrowser() {
 }
 
 bool SetAsDefaultProtocolClient(const std::string& protocol) {
+  base::ThreadRestrictions::AssertIOAllowed();
+
   if (protocol.empty())
     return false;
 
@@ -625,6 +639,8 @@ DefaultWebClientState IsDefaultProtocolClient(const std::string& protocol) {
 namespace win {
 
 bool SetAsDefaultBrowserUsingIntentPicker() {
+  base::ThreadRestrictions::AssertIOAllowed();
+
   base::FilePath chrome_exe;
   if (!PathService::Get(base::FILE_EXE, &chrome_exe)) {
     NOTREACHED() << "Error getting app exe path";
@@ -643,7 +659,7 @@ bool SetAsDefaultBrowserUsingIntentPicker() {
 
 void SetAsDefaultBrowserUsingSystemSettings(
     const base::Closure& on_finished_callback) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   base::FilePath chrome_exe;
   if (!PathService::Get(base::FILE_EXE, &chrome_exe)) {
@@ -670,6 +686,8 @@ void SetAsDefaultBrowserUsingSystemSettings(
 }
 
 bool SetAsDefaultProtocolClientUsingIntentPicker(const std::string& protocol) {
+  base::ThreadRestrictions::AssertIOAllowed();
+
   base::FilePath chrome_exe;
   if (!PathService::Get(base::FILE_EXE, &chrome_exe)) {
     NOTREACHED() << "Error getting app exe path";
@@ -691,7 +709,7 @@ bool SetAsDefaultProtocolClientUsingIntentPicker(const std::string& protocol) {
 void SetAsDefaultProtocolClientUsingSystemSettings(
     const std::string& protocol,
     const base::Closure& on_finished_callback) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  base::ThreadRestrictions::AssertIOAllowed();
 
   base::FilePath chrome_exe;
   if (!PathService::Get(base::FILE_EXE, &chrome_exe)) {
@@ -731,14 +749,12 @@ void MigrateTaskbarPins() {
   if (base::win::GetVersion() < base::win::VERSION_WIN7)
     return;
 
-  // This needs to happen eventually (e.g. so that the appid is fixed and the
-  // run-time Chrome icon is merged with the taskbar shortcut), but this is not
-  // urgent and shouldn't delay Chrome startup.
-  static const int64_t kMigrateTaskbarPinsDelaySeconds = 15;
-  BrowserThread::PostDelayedTask(
-      BrowserThread::FILE, FROM_HERE,
-      base::Bind(&MigrateTaskbarPinsCallback),
-      base::TimeDelta::FromSeconds(kMigrateTaskbarPinsDelaySeconds));
+  // This needs to happen (e.g. so that the appid is fixed and the
+  // run-time Chrome icon is merged with the taskbar shortcut), but it is not an
+  // urgent task.
+  base::PostTaskWithTraits(FROM_HERE,
+                           {base::MayBlock(), base::TaskPriority::BACKGROUND},
+                           base::Bind(&MigrateTaskbarPinsCallback));
 }
 
 void GetIsPinnedToTaskbarState(