Reduce usage of MessageLoopProxy in base/

base/debug/trace_event_memory.cc

Index: base/debug/trace_event_memory.cc
diff --git a/base/debug/trace_event_memory.cc b/base/debug/trace_event_memory.cc
index 5cb09087f57fa404eedee214ef9c80ec3069d0aa..766ca7412290285bf532b34a6745d71a27d4d553 100644
--- a/base/debug/trace_event_memory.cc
+++ b/base/debug/trace_event_memory.cc
@@ -9,7 +9,7 @@
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_loop.h"
+#include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/threading/thread_local_storage.h"
@@ -144,11 +144,11 @@ int GetPseudoStack(int skip_count_ignored, void** stack_out) {
 //////////////////////////////////////////////////////////////////////////////
 
 TraceMemoryController::TraceMemoryController(
-    scoped_refptr<MessageLoopProxy> message_loop_proxy,
+    scoped_refptr<SingleThreadTaskRunner> main_task_runner,
     HeapProfilerStartFunction heap_profiler_start_function,
     HeapProfilerStopFunction heap_profiler_stop_function,
     GetHeapProfileFunction get_heap_profile_function)
-    : message_loop_proxy_(message_loop_proxy),
+    : main_task_runner_(main_task_runner),
       heap_profiler_start_function_(heap_profiler_start_function),
       heap_profiler_stop_function_(heap_profiler_stop_function),
       get_heap_profile_function_(get_heap_profile_function),
@@ -174,10 +174,9 @@ void TraceMemoryController::OnTraceLogEnabled() {
   if (!enabled)
     return;
   DVLOG(1) << "OnTraceLogEnabled";
-  message_loop_proxy_->PostTask(
-      FROM_HERE,
-      base::Bind(&TraceMemoryController::StartProfiling,
-                 weak_factory_.GetWeakPtr()));
+  main_task_runner_->PostTask(FROM_HERE,
+                              base::Bind(&TraceMemoryController::StartProfiling,
+                                         weak_factory_.GetWeakPtr()));
 }
 
 void TraceMemoryController::OnTraceLogDisabled() {
@@ -185,10 +184,9 @@ void TraceMemoryController::OnTraceLogDisabled() {
   // called, so we cannot tell if it was enabled before. Always try to turn
   // off profiling.
   DVLOG(1) << "OnTraceLogDisabled";
-  message_loop_proxy_->PostTask(
-      FROM_HERE,
-      base::Bind(&TraceMemoryController::StopProfiling,
-                 weak_factory_.GetWeakPtr()));
+  main_task_runner_->PostTask(FROM_HERE,
+                              base::Bind(&TraceMemoryController::StopProfiling,
+                                         weak_factory_.GetWeakPtr()));
 }
 
 void TraceMemoryController::StartProfiling() {