favor DCHECK_CURRENTLY_ON for better logs in chrome/browser/chromeos/

chrome/browser/chromeos/memory/low_memory_observer.cc

Index: chrome/browser/chromeos/memory/low_memory_observer.cc
diff --git a/chrome/browser/chromeos/memory/low_memory_observer.cc b/chrome/browser/chromeos/memory/low_memory_observer.cc
index f402225c90277dea797162c85766681032d3978a..fbbb3fd7c7a5bb37850443cdabbddbdabacd1771 100644
--- a/chrome/browser/chromeos/memory/low_memory_observer.cc
+++ b/chrome/browser/chromeos/memory/low_memory_observer.cc
@@ -117,7 +117,7 @@ void LowMemoryObserverImpl::StartObservingOnFileThread() {
   DCHECK_LE(file_descriptor_, 0)
       << "Attempted to start observation when it was already started.";
   DCHECK(watcher_.get() == NULL);
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   DCHECK(base::MessageLoopForIO::current());
 
   file_descriptor_ = ::open(kLowMemFile, O_RDONLY);
@@ -135,7 +135,7 @@ void LowMemoryObserverImpl::StopObservingOnFileThread() {
   // If StartObserving failed, StopObserving will still get called.
   timer_.Stop();
   if (file_descriptor_ >= 0) {
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+    DCHECK_CURRENTLY_ON(BrowserThread::FILE);
     watcher_.reset(NULL);
     ::close(file_descriptor_);
     file_descriptor_ = -1;
@@ -151,7 +151,7 @@ void LowMemoryObserverImpl::ScheduleNextObservation() {
 
 void LowMemoryObserverImpl::StartWatchingDescriptor() {
   DCHECK(watcher_.get());
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   DCHECK(base::MessageLoopForIO::current());
   if (file_descriptor_ < 0)
     return;