[TaskScheduler]: Use ScopedBlockingCall to mark blocking tasks.

This CL uses ScopedBlockingCall to mark blocking calls in /components/download.

This CL was created by replacing calls to AssertBlockingAllowed()
with instantiations of ScopedBlockingCall(MAY_BLOCK).
I kindly ask the reviewer to make sure of the following:
  - ScopedBlockingCall is instantiated in a scope with minimal CPU usage.
    If this is not the case, ScopedBlockingCall should be instantiated
    closer to the blocking call. See scoped_blocking_call.h for more
    info. Please let me know when/where the blocking call happens if this needs
    to be changed.
  - Parameter |blocking_type| matches expectation (MAY_BLOCK/WILL_BLOCK). See
    BlockingType for more info. While I assumed MAY_BLOCK by default, that might
    not be the best fit if we know that this callsite is guaranteed to block.
  - The ScopedBlockingCall's scope covers the entirety of the blocking operation
    previously asserted against by the AssertBlockingAllowed().

This CL was uploaded by git cl split.

R=shaktisahu@chromium.org

TBR=shaktisahu@chromium.org

Bug: 874080
Change-Id: Icf3e527d0d344e099a9debe054a8046273baebef
Reviewed-on: https://chromium-review.googlesource.com/1191096
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594725}

components/download/internal/background_service/file_monitor_impl.cc

@@ -11,7 +11,7 @@
 #include "base/stl_util.h"
 #include "base/sys_info.h"
 #include "base/task_runner_util.h"
-#include "base/threading/thread_restrictions.h"
+#include "base/threading/scoped_blocking_call.h"
 
 namespace download {
 
@@ -24,7 +24,7 @@ bool CalculateDiskUtilization(const base::FilePath& file_dir,
                               int64_t& total_disk_space,
                               int64_t& free_disk_space,
                               int64_t& files_size) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   base::FileEnumerator file_enumerator(file_dir, false /* recursive */,
                                        base::FileEnumerator::FILES);
 
@@ -79,7 +79,7 @@ bool InitializeAndCreateDownloadDirectory(const base::FilePath& dir_path) {
 
 void GetFilesInDirectory(const base::FilePath& directory,
                          std::set<base::FilePath>& paths_out) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   base::FileEnumerator file_enumerator(directory, false /* recursive */,
                                        base::FileEnumerator::FILES);
 
@@ -91,7 +91,7 @@ void GetFilesInDirectory(const base::FilePath& directory,
 
 void DeleteFilesOnFileThread(const std::set<base::FilePath>& paths,
                              stats::FileCleanupReason reason) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   int num_delete_attempted = 0;
   int num_delete_failed = 0;
   int num_delete_by_external = 0;
@@ -116,7 +116,7 @@ void DeleteFilesOnFileThread(const std::set<base::FilePath>& paths,
 void DeleteUnknownFilesOnFileThread(
     const base::FilePath& directory,
     const std::set<base::FilePath>& download_file_paths) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   std::set<base::FilePath> files_in_dir;
   GetFilesInDirectory(directory, files_in_dir);
 
@@ -127,7 +127,7 @@ void DeleteUnknownFilesOnFileThread(
 }
 
 bool HardRecoverOnFileThread(const base::FilePath& directory) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   std::set<base::FilePath> files_in_dir;
   GetFilesInDirectory(directory, files_in_dir);
   DeleteFilesOnFileThread(files_in_dir,

components/download/internal/common/base_file_win.cc

@@ -15,7 +15,7 @@
 #include "base/guid.h"
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/threading/thread_restrictions.h"
+#include "base/threading/scoped_blocking_call.h"
 #include "components/download/public/common/download_interrupt_reasons_utils.h"
 #include "components/download/public/common/download_stats.h"
 
@@ -235,7 +235,7 @@ DownloadInterruptReason MapShFileOperationCodes(int code) {
 // Returns a network error, or net::OK for success.
 DownloadInterruptReason BaseFile::MoveFileAndAdjustPermissions(
     const base::FilePath& new_path) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
 
   // The parameters to SHFileOperation must be terminated with 2 NULL chars.
   base::FilePath::StringType source = full_path_.value();

components/download/quarantine/quarantine_linux.cc

@@ -10,7 +10,7 @@
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
-#include "base/threading/thread_restrictions.h"
+#include "base/threading/scoped_blocking_call.h"
 #include "components/download/quarantine/common_linux.h"
 #include "url/gurl.h"
 
@@ -23,7 +23,7 @@ bool SetExtendedFileAttribute(const char* path,
                               const char* value,
                               size_t value_size,
                               int flags) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   int result = setxattr(path, name, value, value_size, flags);
   if (result) {
     DPLOG(ERROR) << "Could not set extended attribute " << name << " on file "

components/download/quarantine/quarantine_mac.mm

@@ -17,7 +17,7 @@
 #include "base/mac/scoped_cftyperef.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
-#include "base/threading/thread_restrictions.h"
+#include "base/threading/scoped_blocking_call.h"
 #include "components/download/quarantine/common_mac.h"
 #include "url/gurl.h"
 
@@ -99,7 +99,7 @@ namespace {
 bool AddOriginMetadataToFile(const base::FilePath& file,
                              const GURL& source,
                              const GURL& referrer) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   // There's no declaration for MDItemSetAttribute in any known public SDK.
   // It exists in the 10.4 and 10.5 runtimes.  To play it safe, do the lookup
   // at runtime instead of declaring it ourselves and linking against what's
@@ -169,7 +169,7 @@ bool AddOriginMetadataToFile(const base::FilePath& file,
 bool AddQuarantineMetadataToFile(const base::FilePath& file,
                                  const GURL& source,
                                  const GURL& referrer) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
   base::scoped_nsobject<NSMutableDictionary> properties;
   bool success = false;
   if (@available(macos 10.10, *)) {

components/download/quarantine/quarantine_win.cc

@@ -25,7 +25,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/threading/thread_restrictions.h"
+#include "base/threading/scoped_blocking_call.h"
 #include "base/win/scoped_handle.h"
 #include "base/win/win_util.h"
 #include "components/download/quarantine/common_win.h"
@@ -215,7 +215,7 @@ QuarantineFileResult QuarantineFile(const base::FilePath& file,
                                     const GURL& source_url,
                                     const GURL& referrer_url,
                                     const std::string& client_guid) {
-  base::AssertBlockingAllowed();
+  base::ScopedBlockingCall scoped_blocking_call(base::BlockingType::MAY_BLOCK);
 
   int64_t file_size = 0;
   if (!base::PathExists(file) || !base::GetFileSize(file, &file_size))