[code coverage] Don't instrument whole jar file which zero'ed out timestamps

JaCoCO instruments jar file will change zero'ed out timestamps in original jar.
Changed to extract all, instrument class files and zip using build_utils.ZipDir.

Bug: 985581
Change-Id: I79ccdfc474c210af4b71847567c6406f91778505
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1876086
Commit-Queue: Yun Liu <yliuyliu@google.com>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708910}

build/android/gyp/jacoco_instr.py

@@ -143,33 +143,12 @@ def _GetAffectedClasses(jar_file, source_files):
   return affected_classes, unaffected_members
 
 
-def _InstrumentWholeJar(instrument_cmd, input_path, output_path, temp_dir):
-  """Instruments input jar to output_path.
-
-  Args:
-    instrument_cmd: JaCoCo instrument command.
-    input_path: The input path to non-instrumented jar.
-    output_path: The output path to instrumented jar.
-    temp_dir: The temporary directory.
-  """
-  instrument_cmd.extend([input_path, '--dest', temp_dir])
-
-  build_utils.CheckOutput(instrument_cmd)
-
-  jars = os.listdir(temp_dir)
-  if len(jars) != 1:
-    raise Exception('Error: multiple output files: %s' % jars)
-
-  # Delete output_path first to avoid modifying input_path in the case where
-  # input_path is a hardlink to output_path. http://crbug.com/571642
-  if os.path.exists(output_path):
-    os.unlink(output_path)
-  shutil.move(os.path.join(temp_dir, jars[0]), output_path)
-
-
-def _InstrumentClassFiles(instrument_cmd, input_path, output_path, temp_dir,
-                          affected_source_files):
-  """Instruments affected class files from input jar.
+def _InstrumentClassFiles(instrument_cmd,
+                          input_path,
+                          output_path,
+                          temp_dir,
+                          affected_source_files=None):
+  """Instruments class files from input jar.
 
   Args:
     instrument_cmd: JaCoCo instrument command.
@@ -177,9 +156,13 @@ def _InstrumentClassFiles(instrument_cmd, input_path, output_path, temp_dir,
     output_path: The output path to instrumented jar.
     temp_dir: The temporary directory.
     affected_source_files: The affected source file paths to input jar.
+      Default is None, which means instrumenting all class files in jar.
   """
-  affected_classes, unaffected_members = _GetAffectedClasses(
-      input_path, affected_source_files)
+  affected_classes = None
+  unaffected_members = None
+  if affected_source_files:
+    affected_classes, unaffected_members = _GetAffectedClasses(
+        input_path, affected_source_files)
 
   # Extract affected class files.
   with zipfile.ZipFile(input_path) as f:
@@ -191,9 +174,10 @@ def _InstrumentClassFiles(instrument_cmd, input_path, output_path, temp_dir,
   instrument_cmd.extend([temp_dir, '--dest', instrumented_dir])
   build_utils.CheckOutput(instrument_cmd)
 
-  # Extract unaffected members to instrumented_dir.
-  with zipfile.ZipFile(input_path) as f:
-    f.extractall(instrumented_dir, unaffected_members)
+  if affected_source_files and unaffected_members:
+    # Extract unaffected members to instrumented_dir.
+    with zipfile.ZipFile(input_path) as f:
+      f.extractall(instrumented_dir, unaffected_members)
 
   # Zip all files to output_path
   build_utils.ZipDir(output_path, instrumented_dir)
@@ -220,8 +204,8 @@ def _RunInstrumentCommand(parser):
     ]
 
     if not args.files_to_instrument:
-      _InstrumentWholeJar(instrument_cmd, args.input_path, args.output_path,
-                          temp_dir)
+      _InstrumentClassFiles(instrument_cmd, args.input_path, args.output_path,
+                            temp_dir)
     else:
       affected_files = build_utils.ReadSourcesList(args.files_to_instrument)
       source_set = set(source_files)