Only enable heap tracking under --enable-heap-profiling=task-profiler.

base/base_switches.cc

Index: base/base_switches.cc
diff --git a/base/base_switches.cc b/base/base_switches.cc
index f5c6eb3f59bb78f81f313436c11e8609efadd8a1..e8aa5cbc4d5e051dbb61302d434b0598b5c77e6f 100644
--- a/base/base_switches.cc
+++ b/base/base_switches.cc
@@ -24,6 +24,12 @@ const char kEnableHeapProfiling[]           = "enable-heap-profiling";
 // derived from trace events are reported.
 const char kEnableHeapProfilingModeNative[] = "native";
 
+// Report per-task heap usage and churn in the task profiler.
+// Does not keep track of individual allocations unlike the default and native
+// mode. Keeps only track of summarized churn stats in the task profiler
+// (chrome://profiler).
+const char kEnableHeapProfilingTaskProfiler[] = "task-profiler";
+
 // Generates full memory crash dump.
 const char kFullMemoryCrashReport[]         = "full-memory-crash-report";