Add resource_sizes diffs to diagnose_apk_bloat.py.

tools/binary_size/README.md

 # Tools for analyzing Chrome's binary size
 
 # Super Size
 
 Collect, archive, and analyze Chrome's binary size.
 
 ## "archive"
 
 Collect size information and dump it into a `.size` file. Mainly consists of
 symbol information parsed from a linker .map file.
@@ skipping 30 matching lines @@
 
     # Enters a Python REPL (it will print more guidance).
     tools/binary_size/supersize console chrome.size
 
 ## diagnose_apk_bloat.py
 
 Determine the cause of binary size bloat for a patch.
 
 ### Example Usage:
 
-    # Sync, build, and store MonochromePublic.apk for HEAD and HEAD^.
-    tools/binary_size/diagnose_apk_bloat.py -v
+    # Sync, build, and diff for HEAD and HEAD^.
+    tools/binary_size/diagnose_apk_bloat.py
 
     # Display detailed usage info (there are many options).
     tools/binary_size/diagnose_apk_bloat.py -h
 
 # Roadmap for Super Size:
 
 Tracked in https://crbug.com/681694
 
 1. More `archive` features:
 
@@ skipping 20 matching lines @@
 1. Integrate with `resource_sizes.py` so that it tracks size of major
    components separately: chrome vs blink vs skia vs v8.
 1. Speed up some steps (like normalizing names) via multiprocessing.
 1. Add dependency graph info, perhaps just on a per-file basis.
 
 # Roadmap for diagnose_apk_bloat.py:
 1. More `diagnose_apk_bloat.py` features:
 
   * Add diffing functionality to see diff stats for two commits.
   * Add --cloud option for using artifacts from perf builders.