diagnose_bloat.py: update logging and general clean up.

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 42 matching lines @@
     tools/binary_size/supersize console chrome.size
 
 ## "diff"
 
 A convenience command equivalent to: `console before.size after.size --query='Print(Diff(size_info1, size_info2))'`
 
 ### Example Usage:
 
     tools/binary_size/supersize diff before.size after.size --all
 
-# diagnose_apk_bloat.py
+# diagnose_bloat.py
 
-Determine the cause of binary size bloat for a patch.
+Determine the cause of binary size bloat between two commits. Works for Android
+and partially works for Linux (crbug/717550).
 
 ## Example Usage:
 
     # Build and diff HEAD^ and HEAD.
-    tools/binary_size/diagnose_apk_bloat.py HEAD
+    tools/binary_size/diagnose_bloat.py HEAD
 
     # Diff OTHERREV and REV using downloaded build artifacts.
-    tools/binary_size/diagnose_apk_bloat.py REV --reference-rev OTHERREV --cloud
+    tools/binary_size/diagnose_bloat.py REV --reference-rev OTHERREV --cloud
 
-    # Build and diff contiguous revs in range OTHERREV..REV for src/v8.
-    tools/binary_size/diagnose_apk_bloat.py REV --reference-rev OTHERREV --subrepo v8 --all
+    # Build and diff all contiguous revs in range OTHERREV..REV for src/v8.
+    tools/binary_size/diagnose_bloat.py REV --reference-rev OTHERREV --subrepo v8 --all
 
     # Display detailed usage info (there are many options).
-    tools/binary_size/diagnose_apk_bloat.py -h
+    tools/binary_size/diagnose_bloat.py -h
 
 # Roadmap for Super Size:
 
 Tracked in https://crbug.com/681694
 
 1. More `archive` features:
 
   * Find out more about 0xffffffffffffffff addresses, and why such large
     gaps exist after them.
   * Use nm to get the full list of symbols that share the same address.
@@ skipping 12 matching lines @@
 
 1. More `html_report` features:
 
   * Break down by other groupings (e.g. create from nested `SymbolGroups`)
 
 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:
+# Roadmap for diagnose_bloat.py:
+1. More `diagnose_bloat.py` features:
 
   * Add more diff types (pak files, Java symbols).