Reland of Pass SequencedTaskRunner to PowerSaveBlocker for ui/file ops

content/browser/power_save_blocker_chromeos.cc

Index: content/browser/power_save_blocker_chromeos.cc
diff --git a/content/browser/power_save_blocker_chromeos.cc b/content/browser/power_save_blocker_chromeos.cc
index bf50c89845198670935dff49fd4d4970696468f0..2913f093c0f59ffcabbec5c3507708aa559c50ba 100644
--- a/content/browser/power_save_blocker_chromeos.cc
+++ b/content/browser/power_save_blocker_chromeos.cc
@@ -12,7 +12,6 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "chromeos/dbus/power_policy_controller.h"
-#include "content/public/browser/browser_thread.h"
 
 namespace content {
 
@@ -40,11 +39,16 @@ class PowerSaveBlockerImpl::Delegate
  public:
   Delegate(PowerSaveBlockerType type,
            Reason reason,
-           const std::string& description)
-      : type_(type), reason_(reason), description_(description), block_id_(0) {}
+           const std::string& description,
+           scoped_refptr<base::SequencedTaskRunner> ui_task_runner)
+      : type_(type),
+        reason_(reason),
+        description_(description),
+        block_id_(0),
+        ui_task_runner_(ui_task_runner) {}
 
   void ApplyBlock() {
-    DCHECK_CURRENTLY_ON(BrowserThread::UI);
+    DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
     if (!chromeos::PowerPolicyController::IsInitialized())
       return;
 
@@ -64,7 +68,7 @@ class PowerSaveBlockerImpl::Delegate
   }
 
   void RemoveBlock() {
-    DCHECK_CURRENTLY_ON(BrowserThread::UI);
+    DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
     if (!chromeos::PowerPolicyController::IsInitialized())
       return;
 
@@ -82,20 +86,27 @@ class PowerSaveBlockerImpl::Delegate
   // ID corresponding to the block request in PowerPolicyController.
   int block_id_;
 
+  scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
+
   DISALLOW_COPY_AND_ASSIGN(Delegate);
 };
 
-PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
-                                           Reason reason,
-                                           const std::string& description)
-    : delegate_(new Delegate(type, reason, description)) {
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::Bind(&Delegate::ApplyBlock, delegate_));
+PowerSaveBlockerImpl::PowerSaveBlockerImpl(
+    PowerSaveBlockerType type,
+    Reason reason,
+    const std::string& description,
+    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> blocking_task_runner)
+    : delegate_(new Delegate(type, reason, description, ui_task_runner)),
+      ui_task_runner_(ui_task_runner),
+      blocking_task_runner_(blocking_task_runner) {
+  ui_task_runner_->PostTask(FROM_HERE,
+                            base::Bind(&Delegate::ApplyBlock, delegate_));
 }
 
 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::Bind(&Delegate::RemoveBlock, delegate_));
+  ui_task_runner_->PostTask(FROM_HERE,
+                            base::Bind(&Delegate::RemoveBlock, delegate_));
 }
 
 }  // namespace content