Add context for tasks run by TaskGraphRunner

cc/raster/synchronous_task_graph_runner.cc

Index: cc/raster/synchronous_task_graph_runner.cc
diff --git a/cc/raster/synchronous_task_graph_runner.cc b/cc/raster/synchronous_task_graph_runner.cc
index f9c0a65b24e67ffaae99e8fee202d62ee2bbd0b7..daadbcea16ea36667b8b35a6cc44e8e493edfde7 100644
--- a/cc/raster/synchronous_task_graph_runner.cc
+++ b/cc/raster/synchronous_task_graph_runner.cc
@@ -67,6 +67,9 @@ void SynchronousTaskGraphRunner::RunUntilIdle() {
 }
 
 bool SynchronousTaskGraphRunner::RunTask() {
+  // Since we do not have posted from location for tasks, record the context for
+  // tasks as "cc" in heap profiler.
+  TRACE_HEAP_PROFILER_API_SCOPED_TASK_EXECUTION scoped_event("cc");
   TRACE_EVENT0("toplevel", "SynchronousTaskGraphRunner::RunTask");
 
   // Find the first category with any tasks to run. This task graph runner