Add dex classes to dex methods diff by android-binary-size trybot

This cl adds a new diff of class symbols in dex to the current diff of
method symbols.

Bug: 1012371
Change-Id: Ief062e055ad2eb96d22a4534fa4cfdfd8cbf8b3f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1869835
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Auto-Submit: Mohamed Heikal <mheikal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709640}

tools/binary_size/trybot_commit_size_checker.py

@@ -114,12 +114,25 @@ Refer to Mutable Constants Diff for list of symbols.
 
 
 def _CreateMethodCountDelta(symbols):
-  symbols = symbols.WhereInSection(models.SECTION_DEX_METHOD)
-  lines, net_added = _SymbolDiffHelper(symbols)
-  details = 'Refer to Dex Method Diff for list of added/removed methods.'
+  method_symbols = symbols.WhereInSection(models.SECTION_DEX_METHOD)
+  method_lines, net_method_added = _SymbolDiffHelper(method_symbols)
+  class_symbols = symbols.WhereInSection(
+      models.SECTION_DEX).WhereNameMatches('#').Inverted()
+  class_lines, _ = _SymbolDiffHelper(class_symbols)
+  details = (
+      'Refer to Dex Class and Method Diff for list of added/removed methods.')
+  lines = []
+  if class_lines:
+    lines.append('===== Classes Added & Removed =====')
+    lines.extend(class_lines)
+    lines.extend(['', ''])  # empty lines added for clarity
+  if method_lines:
+    lines.append('===== Methods Added & Removed =====')
+    lines.extend(method_lines)
 
   return lines, _SizeDelta('Dex Methods Count', 'methods',
-                           _MAX_DEX_METHOD_COUNT_INCREASE, net_added, details)
+                           _MAX_DEX_METHOD_COUNT_INCREASE, net_method_added,
+                           details)
 
 
 def _CreateResourceSizesDelta(apk_name, before_dir, after_dir):
@@ -291,7 +304,7 @@ PASSING:
           'lines': testing_symbols_lines,
       },
       {
-          'name': '>>> Dex Method Diff <<<',
+          'name': '>>> Dex Class and Method Diff <<<',
           'lines': dex_delta_lines,
       },
       {
@@ -303,7 +316,7 @@ PASSING:
           'url': _HTML_REPORT_BASE_URL + '{{' + _NDJSON_FILENAME + '}}',
       },
   ]
-  # Remove empty diffs (Mutable Constants or Dex Method).
+  # Remove empty diffs (Mutable Constants, Dex Method, ...).
   links_json = [o for o in links_json if o.get('lines') or o.get('url')]
 
   binary_size_listings = []