Downloads: replace BrowserThread::FILE with task scheduler.

content/browser/download/base_file.cc

Index: content/browser/download/base_file.cc
diff --git a/content/browser/download/base_file.cc b/content/browser/download/base_file.cc
index 7c05f8deac393f8141a7006a039a758341635663..0c35f2eb90247ee3eb75e5ff2b0429a55f1b3484 100644
--- a/content/browser/download/base_file.cc
+++ b/content/browser/download/base_file.cc
@@ -18,7 +18,6 @@
 #include "content/browser/download/download_interrupt_reasons_impl.h"
 #include "content/browser/download/download_net_log_parameters.h"
 #include "content/browser/download/download_stats.h"
-#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/quarantine.h"
 #include "crypto/secure_hash.h"
@@ -28,10 +27,12 @@
 
 namespace content {
 
-BaseFile::BaseFile(const net::NetLogWithSource& net_log) : net_log_(net_log) {}
+BaseFile::BaseFile(const net::NetLogWithSource& net_log) : net_log_(net_log) {
+  DETACH_FROM_SEQUENCE(sequence_checker_);
+}
 
 BaseFile::~BaseFile() {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   if (detached_)
     Close();
   else
@@ -46,7 +47,7 @@ DownloadInterruptReason BaseFile::Initialize(
     const std::string& hash_so_far,
     std::unique_ptr<crypto::SecureHash> hash_state,
     bool is_sparse_file) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!detached_);
 
   if (full_path.empty()) {
@@ -127,7 +128,7 @@ DownloadInterruptReason BaseFile::WriteDataToFile(int64_t offset,
 }
 
 DownloadInterruptReason BaseFile::Rename(const base::FilePath& new_path) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DownloadInterruptReason rename_result = DOWNLOAD_INTERRUPT_REASON_NONE;
 
   // If the new path is same as the old one, there is no need to perform the
@@ -172,7 +173,7 @@ void BaseFile::Detach() {
 }
 
 void BaseFile::Cancel() {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!detached_);
 
   net_log_.AddEvent(net::NetLogEventType::CANCELLED);
@@ -188,7 +189,7 @@ void BaseFile::Cancel() {
 }
 
 std::unique_ptr<crypto::SecureHash> BaseFile::Finish() {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   // TODO(qinmin): verify that all the holes have been filled.
   if (is_sparse_file_)
@@ -276,7 +277,7 @@ DownloadInterruptReason BaseFile::CalculatePartialHash(
 }
 
 DownloadInterruptReason BaseFile::Open(const std::string& hash_so_far) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!detached_);
   DCHECK(!full_path_.empty());
 
@@ -339,7 +340,7 @@ DownloadInterruptReason BaseFile::Open(const std::string& hash_so_far) {
 }
 
 void BaseFile::Close() {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
   if (file_.IsValid()) {
     // Currently we don't really care about the return value, since if it fails
@@ -426,7 +427,7 @@ DownloadInterruptReason BaseFile::AnnotateWithSourceInformation(
     const std::string& client_guid,
     const GURL& source_url,
     const GURL& referrer_url) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK(!detached_);
   DCHECK(!full_path_.empty());