General comment cleaning / refactoring for Mac Installer

chrome/installer/mac/app/testing/Unpacker_test.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/installer/mac/app/Unpacker.h"
 
 #include "base/base_paths.h"
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "base/strings/sys_string_conversions.h"
@@ skipping 56 matching lines @@
 }
 - (void)unpacker:(Unpacker*)unpacker onUnmountFailure:(NSError*)error {
   [self fail];
 }
 
 @end
 
 namespace {
 
 TEST(UnpackerTest, IntegrationTest) {
-  // create objects and semaphore
+  // Create objects and semaphore
   Unpacker* unpack = [[Unpacker alloc] init];
   TestDelegate* test_delegate = [[TestDelegate alloc] init];
   unpack.delegate = test_delegate;
 
-  // get a disk image to use to test
+  // Get a disk image to use to test
   base::FilePath originalPath;
   PathService::Get(base::DIR_SOURCE_ROOT, &originalPath);
   originalPath = originalPath.AppendASCII("chrome/test/data/mac_installer/");
   base::FilePath copiedPath = base::FilePath(originalPath);
   NSString* diskImageOriginalPath = base::SysUTF8ToNSString(
       (originalPath.AppendASCII("test-dmg.dmg")).value());
   NSString* diskImageCopiedPath = base::SysUTF8ToNSString(
       (originalPath.AppendASCII("test-dmg2.dmg")).value());
+  // The unpacker moves (not copies) a downloaded disk image directly into its
+  // own temporary directory, so if the below copy didn't happen, `test-dmg.dmg`
+  // would disappear every time this test was run
   [[NSFileManager defaultManager] copyItemAtPath:diskImageOriginalPath
                                           toPath:diskImageCopiedPath
                                            error:nil];
   NSURL* dmgURL = [NSURL fileURLWithPath:diskImageCopiedPath isDirectory:NO];
-  // start mount step
+  // Start mount step
   [unpack mountDMGFromURL:dmgURL];
   [test_delegate wait];
 
-  // is the disk image mounted?
+  // Is the disk image mounted?
   ASSERT_TRUE([test_delegate pass]);
 
-  // start unmount step
+  // Start unmount step
   [unpack unmountDMG];
   [test_delegate wait];
 
-  // is the disk image gone?
+  // Is the disk image gone?
   EXPECT_TRUE([test_delegate pass]);
 }
 
 }  // namespace