Reduce usage of MessageLoopProxy in base/

base/debug/trace_event_memory.h

Index: base/debug/trace_event_memory.h
diff --git a/base/debug/trace_event_memory.h b/base/debug/trace_event_memory.h
index 4caeef4de855a1ed383a297bd510b28d884aca51..3a84dff873c11e16392147af06fcb9fbf8a9e855 100644
--- a/base/debug/trace_event_memory.h
+++ b/base/debug/trace_event_memory.h
@@ -20,7 +20,7 @@
 
 namespace base {
 
-class MessageLoopProxy;
+class SingleThreadTaskRunner;
 
 namespace debug {
 
@@ -35,15 +35,14 @@ class BASE_EXPORT TraceMemoryController
   typedef void (*HeapProfilerStopFunction)();
   typedef char* (*GetHeapProfileFunction)();
 
-  // |message_loop_proxy| must be a proxy to the primary thread for the client
-  // process, e.g. the UI thread in a browser. The function pointers must be
-  // pointers to tcmalloc heap profiling functions; by avoiding direct calls to
-  // these functions we avoid a dependency on third_party/tcmalloc from base.
-  TraceMemoryController(
-      scoped_refptr<MessageLoopProxy> message_loop_proxy,
-      HeapProfilerStartFunction heap_profiler_start_function,
-      HeapProfilerStopFunction heap_profiler_stop_function,
-      GetHeapProfileFunction get_heap_profile_function);
+  // |main_task_runner| must be the primary thread for the client process, e.g.
+  // the UI thread in a browser. The function pointers must be pointers to
+  // tcmalloc heap profiling functions; by avoiding direct calls to these
+  // functions we avoid a dependency on third_party/tcmalloc from base.
+  TraceMemoryController(scoped_refptr<SingleThreadTaskRunner> main_task_runner,
+                        HeapProfilerStartFunction heap_profiler_start_function,
+                        HeapProfilerStopFunction heap_profiler_stop_function,
+                        GetHeapProfileFunction get_heap_profile_function);
   virtual ~TraceMemoryController();
 
   // base::debug::TraceLog::EnabledStateChangedObserver overrides:
@@ -65,7 +64,7 @@ class BASE_EXPORT TraceMemoryController
   bool IsTimerRunningForTest() const;
 
   // Ensures the observer starts and stops tracing on the primary thread.
-  scoped_refptr<MessageLoopProxy> message_loop_proxy_;
+  scoped_refptr<SingleThreadTaskRunner> main_task_runner_;
 
   // Pointers to tcmalloc heap profiling functions. Allows this class to use
   // tcmalloc functions without introducing a dependency from base to tcmalloc.