Do not call SequencedWorkerPool::GetWorkerPoolForCurrentThread() from CollectEnvironmentData().

chrome/browser/safe_browsing/incident_reporting/environment_data_collection.cc

Index: chrome/browser/safe_browsing/incident_reporting/environment_data_collection.cc
diff --git a/chrome/browser/safe_browsing/incident_reporting/environment_data_collection.cc b/chrome/browser/safe_browsing/incident_reporting/environment_data_collection.cc
index 0d0b7d308833718e4e2baaf68d16d39b7368e9db..97b8344ebb214f88742d46392447ee5a52771b37 100644
--- a/chrome/browser/safe_browsing/incident_reporting/environment_data_collection.cc
+++ b/chrome/browser/safe_browsing/incident_reporting/environment_data_collection.cc
@@ -9,6 +9,7 @@
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/cpu.h"
+#include "base/logging.h"
 #include "base/sys_info.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/sequenced_worker_pool.h"
@@ -16,6 +17,7 @@
 #include "chrome/common/channel_info.h"
 #include "chrome/common/safe_browsing/csd.pb.h"
 #include "components/version_info/version_info.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace safe_browsing {
 
@@ -68,8 +70,10 @@ void CollectProcessData(ClientIncidentReport_EnvironmentData_Process* process) {
 
 void CollectEnvironmentData(ClientIncidentReport_EnvironmentData* data) {
   // Toggling priority only makes sense in a thread pool.
-  DCHECK(base::SequencedWorkerPool::GetWorkerPoolForCurrentThread());
+  DCHECK(content::BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());

[gab, 2016/09/30 15:48:56]

I think such a call site once again argues for something like
TaskScheduler::RunsTasksOnCurrentThread() in the future.

i.e. for people that want to document that their code runs in a pool without
caring about which specific TaskRunner.

Here I could see something like this match the comment on the line above better:

DCHECK(base::SequencedWorkerPool::GetWorkerPoolForCurrentThread() ||
       base::TaskScheduler::RunsTasksOnCurrentThread());

[gab, 2016/09/30 19:21:03]

Thinking about this some more, WDYT of
DCHECK(!base::ThreadTaskRunnerHandle::IsSet()); here? That would also match
"only makes sense in a thread pool" which is really  meant to say "doesn't make
sense in a single-threaded environment"

[gab, 2016/10/03 19:47:34]

ping ^^?

   // Reset priority when done with this task.
+  // TODO(fdoray): Post this task to the TaskScheduler with a BACKGROUND
+  // priority instead of toggling the priority within the task.
   base::ScopedClosureRunner restore_priority(
       base::Bind(&base::PlatformThread::SetCurrentThreadPriority,
                  base::PlatformThread::GetCurrentThreadPriority()));