Remove remaining calls to deprecated MessageLoop methods on Mac.

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index fc3a0e426f3a3daff6bc5e02253b43778604a5cc..0dc3ef091766a161c2af2c3a9f3e4e66f8a37342 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -21,7 +21,6 @@
 #import "base/mac/scoped_nsobject.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/memory/ref_counted.h"
-#include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/string_util.h"
@@ -29,6 +28,7 @@
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 #import "content/browser/accessibility/browser_accessibility_mac.h"
@@ -1131,9 +1131,9 @@ void RenderWidgetHostViewMac::OnSetNeedsBeginFrames(bool needs_begin_frames) {
 void RenderWidgetHostViewMac::KillSelf() {
   if (!weak_factory_.HasWeakPtrs()) {
     [cocoa_view_ setHidden:YES];
-    base::MessageLoop::current()->PostTask(FROM_HERE,
-        base::Bind(&RenderWidgetHostViewMac::ShutdownHost,
-                   weak_factory_.GetWeakPtr()));
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&RenderWidgetHostViewMac::ShutdownHost,
+                              weak_factory_.GetWeakPtr()));
   }
 }