[SuperSize] Basic refactoring to archive with multiple containers.

To accommodate .aab files and TriChrome, we'd like SuperSize to handle
multiple "containers" and store data in a single .size file.

This CL performs refactoring archive.py to prepare for extending
SuperSize for multiple containers. Details:
* Move temp-file extraction logic with |args.minimal_apks_file| depper,
  into _DeduceMainPaths().
  * Remove |args.extracted_minimal_apk_path|.
* CreateSizeInfo():
  * Change params to take lists of
    {metadata, section_sizes, raw_symbols}.
  * Implementation TODO; keep old behavior by simply using the first
    element of the above.
* _DeduceMainPaths():
  * Change to a generator that yield multiple param sets, one for each
    container.
  * Resolve |apk_prefix| and |apk_path| as separate concepts.
  * Move most of the logic to _Inner() function.
  * Split out _DeduceAuxPaths().
* Run():
  * Merge with _RunInternal().
  * Main action changes:
    * Visits param sets generated from _DeduceMainPaths().
    * Potentially create multiple
      {metadata, section_sizes, raw_symbols},
      now stored into |*_list| variables.

Bug: 900259, 1040645
Change-Id: Ib158f3d5c8b11567f09826fd0c0b31729f4e065c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2125388Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754466}

tools/binary_size/libsupersize/file_format.py

@@ -233,13 +233,15 @@ def _SaveSizeInfoToFile(size_info,
 
   Args:
     size_info: Data to write to the file
-    file_obj: File opened for writing
-    sparse_symbols: If present, only save these symbols to the file
+    file_obj: File opened for writing.
+    include_padding: Whether to save padding data, useful if adding a subset of
+      symbols.
+    sparse_symbols: If present, only save these symbols to the file.
   """
   if sparse_symbols is not None:
-    # Any aliases of sparse symbols must also be included, or else file parsing
-    # will attribute symbols that happen to follow an incomplete alias group to
-    # that alias group.
+    # Any aliases of sparse symbols must also be included, or else file
+    # parsing will attribute symbols that happen to follow an incomplete alias
+    # group to that alias group.
     raw_symbols = _ExpandSparseSymbols(sparse_symbols)
   else:
     raw_symbols = size_info.raw_symbols
@@ -362,7 +364,7 @@ def _ReadValuesFromLine(file_iter, split):
 def _LoadSizeInfoFromFile(file_obj, size_path):
   """Loads a size_info from the given file.
 
-  See _SaveSizeInfoToFile for details on the .size file format.
+  See _SaveSizeInfoToFile() for details on the .size file format.
 
   Args:
     file_obj: File to read, should be a GzipFile

tools/binary_size/libsupersize/integration_test.py

@@ -216,7 +216,7 @@ class IntegrationTest(unittest.TestCase):
             size_info_prefix=size_info_prefix,
             knobs=knobs)
         IntegrationTest.cached_size_info[cache_key] = archive.CreateSizeInfo(
-            section_sizes, raw_symbols, metadata=metadata)
+            [section_sizes], [raw_symbols], [metadata])
     return copy.deepcopy(IntegrationTest.cached_size_info[cache_key])
 
   def _DoArchive(self,