Add supports for nested breakdown in 'dmprof cat'.

tools/deep_memory_profiler/templates.json

Index: tools/deep_memory_profiler/templates.json
diff --git a/tools/deep_memory_profiler/templates.json b/tools/deep_memory_profiler/templates.json
new file mode 100644
index 0000000000000000000000000000000000000000..b4d9a4eb6089ba58e24569eae1b49c49cb341a3d
--- /dev/null
+++ b/tools/deep_memory_profiler/templates.json
@@ -0,0 +1,12 @@
+{
+  "l2": ["vm", "map", {
+    "mmap-tcmalloc": ["malloc", "component", {}]
+  }],
+  "details": ["vm", "map", {
+    "mmap-tcmalloc": ["malloc", "component", {
+      "webkit": ["malloc", "webkit-details", {}],
+      "skia": ["malloc", "skia-details", {}]
+    }],
+    "mmap-v8-heap": ["javascript", "type", {}]
+  }]
+}