Provide a mechanism for dumping of heap profiles on predefined events.

runtime/vm/exceptions.cc

Index: runtime/vm/exceptions.cc
diff --git a/runtime/vm/exceptions.cc b/runtime/vm/exceptions.cc
index f56af6a37e6969a6809bd57defe43c81c5754ac3..20e555cf91db0693dcc73d69bbabe8c4b505b35f 100644
--- a/runtime/vm/exceptions.cc
+++ b/runtime/vm/exceptions.cc
@@ -9,6 +9,7 @@
 #include "vm/debugger.h"
 #include "vm/flags.h"
 #include "vm/object.h"
+#include "vm/object_store.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
@@ -16,7 +17,9 @@
 namespace dart {
 
 DEFINE_FLAG(bool, print_stacktrace_at_throw, false,
-    "Prints a stack trace everytime a throw occurs.");
+            "Prints a stack trace everytime a throw occurs.");
+DEFINE_FLAG(bool, heap_profile_out_of_memory, false,
+            "Writes a heap profile on unhandled out-of-memory exceptions.");
 
 
 const char* Exceptions::kCastErrorDstName = "type cast";