Revert of Pass SequencedTaskRunner to PowerSaveBlocker for ui/file operations

content/browser/power_save_blocker_android.cc

Index: content/browser/power_save_blocker_android.cc
diff --git a/content/browser/power_save_blocker_android.cc b/content/browser/power_save_blocker_android.cc
index 34ff852a039739d4b3376497f20915d91c36efb1..0adcd290d5e024a69d6866cdf0978cd1e4b848d1 100644
--- a/content/browser/power_save_blocker_android.cc
+++ b/content/browser/power_save_blocker_android.cc
@@ -9,6 +9,7 @@
 #include "content/browser/power_save_blocker_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/android/content_view_core.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "jni/PowerSaveBlocker_jni.h"
 #include "ui/android/view_android.h"
@@ -21,8 +22,7 @@
     : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate>,
       public WebContentsObserver {
  public:
-  Delegate(WebContents* web_contents,
-           scoped_refptr<base::SequencedTaskRunner> ui_task_runner);
+  explicit Delegate(WebContents* web_contents);
 
   // Does the actual work to apply or remove the desired power save block.
   void ApplyBlock();
@@ -36,15 +36,11 @@
 
   base::android::ScopedJavaGlobalRef<jobject> java_power_save_blocker_;
 
-  scoped_refptr<base::SequencedTaskRunner> ui_task_runner_;
-
   DISALLOW_COPY_AND_ASSIGN(Delegate);
 };
 
-PowerSaveBlockerImpl::Delegate::Delegate(
-    WebContents* web_contents,
-    scoped_refptr<base::SequencedTaskRunner> ui_task_runner)
-    : WebContentsObserver(web_contents), ui_task_runner_(ui_task_runner) {
+PowerSaveBlockerImpl::Delegate::Delegate(WebContents* web_contents)
+    : WebContentsObserver(web_contents) {
   JNIEnv* env = AttachCurrentThread();
   java_power_save_blocker_.Reset(Java_PowerSaveBlocker_create(env));
 }
@@ -53,7 +49,7 @@
 }
 
 void PowerSaveBlockerImpl::Delegate::ApplyBlock() {
-  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   base::android::ScopedJavaLocalRef<jobject> java_content_view_core =
       GetContentViewCore();
   if (java_content_view_core.is_null())
@@ -66,7 +62,7 @@
 }
 
 void PowerSaveBlockerImpl::Delegate::RemoveBlock() {
-  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   base::android::ScopedJavaLocalRef<jobject> java_content_view_core =
       GetContentViewCore();
   if (java_content_view_core.is_null())
@@ -91,30 +87,26 @@
   return content_view_core_impl->GetJavaObject();
 }
 
-PowerSaveBlockerImpl::PowerSaveBlockerImpl(
-    PowerSaveBlockerType type,
-    Reason reason,
-    const std::string& description,
-    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
-    scoped_refptr<base::SequencedTaskRunner> blocking_task_runner)
-    : ui_task_runner_(ui_task_runner),
-      blocking_task_runner_(blocking_task_runner) {
+PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
+                                           Reason reason,
+                                           const std::string& description) {
   // Don't support kPowerSaveBlockPreventAppSuspension
 }
 
 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
   if (delegate_.get()) {
-    ui_task_runner_->PostTask(FROM_HERE,
-                              base::Bind(&Delegate::RemoveBlock, delegate_));
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&Delegate::RemoveBlock, delegate_));
   }
 }
 
 void PowerSaveBlockerImpl::InitDisplaySleepBlocker(WebContents* web_contents) {
-  DCHECK(ui_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (!web_contents)
     return;
 
-  delegate_ = new Delegate(web_contents, ui_task_runner_);
+  delegate_ = new Delegate(web_contents);
   delegate_->ApplyBlock();
 }