Revert of cc: Control defer_commits logic by Scheduler

cc/trees/layer_tree_host_unittest_context.cc

Index: cc/trees/layer_tree_host_unittest_context.cc
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index a15b60aca4ae60241d78cadd8407825a027bc996..49f7e170632b7b739a01631b79ae53a60856e0f1 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -1776,7 +1776,12 @@
     deferred_ = true;
 
     // Defer commits before the BeginFrame arrives, causing it to be delayed.
-    PostSetDeferCommitsToMainThread(true);
+    MainThreadTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&LayerTreeHostContextTestLoseAfterSendingBeginMainFrame::
+                       DeferCommitsOnMainThread,
+                   base::Unretained(this),
+                   true));
     // Meanwhile, lose the context while we are in defer commits.
     ImplThreadTaskRunner()->PostTask(
         FROM_HERE,
@@ -1789,7 +1794,16 @@
     LoseContext();
 
     // After losing the context, stop deferring commits.
-    PostSetDeferCommitsToMainThread(false);
+    MainThreadTaskRunner()->PostTask(
+        FROM_HERE,
+        base::Bind(&LayerTreeHostContextTestLoseAfterSendingBeginMainFrame::
+                       DeferCommitsOnMainThread,
+                   base::Unretained(this),
+                   false));
+  }
+
+  void DeferCommitsOnMainThread(bool defer_commits) {
+    layer_tree_host()->SetDeferCommits(defer_commits);
   }
 
   void WillBeginMainFrame() override {