Replace MessageLoopProxy usage with ThreadTaskRunnerHandle in chrome/browser module.

MessageLoopProxy is deprecated.
This basically does a search and replace of:

MessageLoopProxy::current() -> ThreadTaskRunnerHandle::Get().

MessageLoopProxy -> SingleThreadTaskRunner

BUG=391045

Review URL: https://codereview.chromium.org/1112403005

Cr-Commit-Position: refs/heads/master@{#328310}
diff --git a/chrome/browser/image_decoder.cc b/chrome/browser/image_decoder.cc
index c3973a5..cb758e5 100644
--- a/chrome/browser/image_decoder.cc
+++ b/chrome/browser/image_decoder.cc
@@ -160,8 +160,8 @@
 void ImageDecoder::StartBatchMode() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   utility_process_host_ =
-      UtilityProcessHost::Create(this, base::MessageLoopProxy::current().get())
-          ->AsWeakPtr();
+      UtilityProcessHost::Create(
+          this, base::ThreadTaskRunnerHandle::Get().get())->AsWeakPtr();
   utility_process_host_->SetName(l10n_util::GetStringUTF16(
       IDS_UTILITY_PROCESS_IMAGE_DECODER_NAME));
   if (!utility_process_host_->StartBatchMode()) {