Supersize: Categorize pak artifacts as overhead

This compression overhead should be a padding-only symbol since it is
purely overhead that is inactionable.

Bug: 826008
Change-Id: I6d2b21676d3cd41efdb738d1c85b4f783dff9286
Reviewed-on: https://chromium-review.googlesource.com/995964Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: Peter Wen <wnwen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548087}

tools/binary_size/libsupersize/archive.py

@@ -453,17 +453,16 @@ def _CalculatePadding(raw_symbols):
 
   Symbols must already be sorted by |address|.
   """
-  seen_sections = []
+  seen_sections = set()
   for i, symbol in enumerate(raw_symbols[1:]):
     prev_symbol = raw_symbols[i]
     if symbol.IsOverhead():
       # Overhead symbols are not actionable so should be padding-only.
       symbol.padding = symbol.size
-      continue
     if prev_symbol.section_name != symbol.section_name:
       assert symbol.section_name not in seen_sections, (
           'Input symbols must be sorted by section, then address.')
-      seen_sections.append(symbol.section_name)
+      seen_sections.add(symbol.section_name)
       continue
     if (symbol.address <= 0 or prev_symbol.address <= 0 or
         not symbol.IsNative() or not prev_symbol.IsNative()):
@@ -768,7 +767,7 @@ def _ParsePakSymbols(
   # Attribute excess to translations since only those are compressed.
   raw_symbols.append(models.Symbol(
       models.SECTION_PAK_TRANSLATIONS, int(round(raw_total - int_total)),
-      full_name='Pak compression leftover artifacts'))
+      full_name='Overhead: Pak compression artifacts'))
 
   for symbol in raw_symbols:
     prev = section_sizes.setdefault(symbol.section_name, 0)

tools/binary_size/libsupersize/testdata/Archive_Apk.golden

@@ -294,7 +294,7 @@ Section .other: has 100.0% of 33984483 bytes accounted for from 2 symbols. 0 byt
 .bss@2dffe80(size_without_padding=4,padding=196,full_name=SaveHistogram(_JNIEnv*, base::android::JavaParamRef<_jobject*> const&, base::android::JavaParamRef<_jstring*> const&, base::android::JavaParamRef<_jlongArray*> const&, int)::atomic_histogram_pointer,object_path=third_party/icu/icuuc/ucnv_ext.o,source_path=third_party/icu/ucnv_ext.c,flags={gen},num_aliases=1)
 .bss@2dffe84(size_without_padding=4,padding=0,full_name=g_AnimationFrameTimeHistogram_clazz,object_path=third_party/icu/icuuc/ucnv_ext.o,source_path=third_party/icu/ucnv_ext.c,flags={anon,gen},num_aliases=1)
 .pak.translations@0(size_without_padding=18,padding=0,full_name=assets/en-US.pak: overhead,object_path=,source_path=,flags={},num_aliases=1)
-.pak.translations@0(size_without_padding=0,padding=0,full_name=Pak compression leftover artifacts,object_path=,source_path=,flags={},num_aliases=1)
+.pak.translations@0(size_without_padding=0,padding=0,full_name=Overhead: Pak compression artifacts,object_path=,source_path=,flags={},num_aliases=1)
 .pak.translations@3ac6(size_without_padding=40,padding=0,full_name=../../components/app_modal_strings.grdp: IDS_BEFOREUNLOAD_MESSAGEBOX_MESSAGE,object_path=,source_path=,flags={},num_aliases=1)
 .pak.translations@3d7c(size_without_padding=24,padding=0,full_name=../../components/policy_strings.grdp: IDS_POLICY_TYPE_ERROR,object_path=,source_path=,flags={},num_aliases=1)
 .pak.translations@3d82(size_without_padding=25,padding=0,full_name=../../components/policy_strings.grdp: IDS_POLICY_LIST_ENTRY_ERROR,object_path=,source_path=,flags={},num_aliases=1)

tools/binary_size/libsupersize/testdata/Archive_Pak_Files.golden

@@ -93,7 +93,7 @@ Section .other: has 100.0% of 33984171 bytes accounted for from 1 symbols. 0 byt
 .bss@2dffe80(size_without_padding=4,padding=196,full_name=SaveHistogram(_JNIEnv*, base::android::JavaParamRef<_jobject*> const&, base::android::JavaParamRef<_jstring*> const&, base::android::JavaParamRef<_jlongArray*> const&, int)::atomic_histogram_pointer,object_path=third_party/icu/icuuc/ucnv_ext.o,source_path=third_party/icu/ucnv_ext.c,flags={gen},num_aliases=1)
 .bss@2dffe84(size_without_padding=4,padding=0,full_name=g_AnimationFrameTimeHistogram_clazz,object_path=third_party/icu/icuuc/ucnv_ext.o,source_path=third_party/icu/ucnv_ext.c,flags={anon,gen},num_aliases=1)
 .pak.translations@0(size_without_padding=18,padding=0,full_name=../mock_apk/assets/en-US.pak: overhead,object_path=,source_path=,flags={},num_aliases=1)
-.pak.translations@0(size_without_padding=0,padding=0,full_name=Pak compression leftover artifacts,object_path=,source_path=,flags={},num_aliases=1)
+.pak.translations@0(size_without_padding=0,padding=0,full_name=Overhead: Pak compression artifacts,object_path=,source_path=,flags={},num_aliases=1)
 .pak.translations@3ac6(size_without_padding=40,padding=0,full_name=../../components/app_modal_strings.grdp: IDS_BEFOREUNLOAD_MESSAGEBOX_MESSAGE,object_path=,source_path=,flags={},num_aliases=1)
 .pak.translations@3d7c(size_without_padding=24,padding=0,full_name=../../components/policy_strings.grdp: IDS_POLICY_TYPE_ERROR,object_path=,source_path=,flags={},num_aliases=1)
 .pak.translations@3d82(size_without_padding=25,padding=0,full_name=../../components/policy_strings.grdp: IDS_POLICY_LIST_ENTRY_ERROR,object_path=,source_path=,flags={},num_aliases=1)