Add initial version of retainers heap profile.

src/SConscript

Index: src/SConscript
diff --git a/src/SConscript b/src/SConscript
index a1cbf1ba291c3455b6989d8a508e371eea25fa1b..423064782a624c9dcad06072da4c3718b9dcd58f 100755
--- a/src/SConscript
+++ b/src/SConscript
@@ -42,14 +42,15 @@ SOURCES = {
     'debug.cc', 'debug-agent.cc', 'disassembler.cc', 'execution.cc',
     'factory.cc', 'flags.cc', 'frame-element.cc', 'frames.cc',
     'func-name-inferrer.cc', 'global-handles.cc', 'handles.cc',
-    'hashmap.cc', 'heap.cc', 'ic.cc', 'interpreter-irregexp.cc',
-    'jsregexp.cc', 'jump-target.cc', 'log.cc', 'log-utils.cc',
-    'mark-compact.cc', 'messages.cc', 'objects.cc', 'oprofile-agent.cc',
-    'parser.cc', 'property.cc', 'regexp-macro-assembler.cc',
-    'regexp-macro-assembler-irregexp.cc', 'regexp-stack.cc',
-    'register-allocator.cc', 'rewriter.cc', 'runtime.cc', 'scanner.cc',
-    'scopeinfo.cc', 'scopes.cc', 'serialize.cc', 'snapshot-common.cc',
-    'spaces.cc', 'string-stream.cc', 'stub-cache.cc', 'token.cc', 'top.cc',
+    'hashmap.cc', 'heap.cc', 'heap-profiler.cc', 'ic.cc',
+    'interpreter-irregexp.cc', 'jsregexp.cc', 'jump-target.cc',
+    'log.cc', 'log-utils.cc', 'mark-compact.cc', 'messages.cc',
+    'objects.cc', 'oprofile-agent.cc', 'parser.cc', 'property.cc',
+    'regexp-macro-assembler.cc', 'regexp-macro-assembler-irregexp.cc',
+    'regexp-stack.cc', 'register-allocator.cc', 'rewriter.cc',
+    'runtime.cc', 'scanner.cc', 'scopeinfo.cc', 'scopes.cc',
+    'serialize.cc', 'snapshot-common.cc', 'spaces.cc',
+    'string-stream.cc', 'stub-cache.cc', 'token.cc', 'top.cc',
     'unicode.cc', 'usage-analyzer.cc', 'utils.cc', 'v8-counters.cc',
     'v8.cc', 'v8threads.cc', 'variables.cc', 'version.cc',
     'virtual-frame.cc', 'zone.cc'