Reland of Add deduplication logic to .pak files

build/android/resource_sizes.py

Index: build/android/resource_sizes.py
diff --git a/build/android/resource_sizes.py b/build/android/resource_sizes.py
index 76f03fb4e30f41c81589e574491823e04c8f171d..099f71dec8b6aff80dd142a974bb75c583b9d974 100755
--- a/build/android/resource_sizes.py
+++ b/build/android/resource_sizes.py
@@ -562,12 +562,17 @@
   # Calculate aggregate stats about resources across pak files.
   resource_count_map = collections.defaultdict(int)
   resource_size_map = collections.defaultdict(int)
+  seen_data_ids = set()
+  alias_overhead_bytes = 4
   resource_overhead_bytes = 6
   for pak in paks:
-    for r in pak.resources:
-      resource_count_map[r] += 1
-      resource_size_map[r] += len(pak.resources[r]) + resource_overhead_bytes
-
+    for k, v in pak.resources.iteritems():
+      resource_count_map[k] += 1
+      if id(v) not in seen_data_ids:
+        seen_data_ids.add(id(v))
+        resource_size_map[k] += resource_overhead_bytes + len(v)
+      else:
+        resource_size_map[k] += alias_overhead_bytes
   # Output the overall resource summary.
   total_resource_size = sum(resource_size_map.values())
   total_resource_count = len(resource_count_map)