Revert "appcache: delete appcache directory from profile when disabled"

This reverts commit bd17f198.

Reason for revert: Test is flaky, especially on Fuchsia bots.

Original change's description:
> appcache: delete appcache directory from profile when disabled
> 
> Once AppCache has been removed from Chrome, sites will have no way of
> cleaning up user data in local profiles.  To fix this, when a storage
> partition is accessed when AppCache has been disabled, we will delete
> the AppCache directory from that profile directory.
> 
> Bug: 1081897
> Change-Id: Iea404f7c83595ba1397fab4a5d3f97d1e3280916
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343588
> Commit-Queue: enne <enne@chromium.org>
> Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
> Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#796938}

TBR=kinuko@chromium.org,mek@chromium.org,enne@chromium.org

Change-Id: Ic43fce0f9ad605a7bfb3a291a320e45d8c329b9d
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1081897, 1115296
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2351834Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797219}

chrome/browser/flag_descriptions.cc

@@ -170,8 +170,7 @@ const char kAppCacheName[] = "AppCache web API and browser backend";
 const char kAppCacheDescription[] =
     "When disabled, turns off all AppCache code so that developers "
     "can test that their code works properly in the future when AppCache "
-    "has been removed.  If disabled, this will also delete any AppCache data "
-    "from profile directories.";
+    "has been removed.";
 
 const char kDnsHttpssvcName[] = "Support for HTTPSSVC records in DNS.";
 const char kDnsHttpssvcDescription[] =

content/browser/storage_partition_impl_map.cc

@@ -451,14 +451,6 @@ void StoragePartitionImplMap::PostCreateInitialization(
         in_memory ? base::FilePath()
                   : partition->GetPath().Append(kAppCacheDirname),
         browser_context_, browser_context_->GetSpecialStoragePolicy());
-  } else if (!in_memory) {
-    // If AppCache is not enabled, clean up any on disk storage.  This is the
-    // path that will execute once AppCache has been fully removed from Chrome.
-    base::ThreadPool::PostTask(
-        FROM_HERE, {base::MayBlock(), base::TaskPriority::BEST_EFFORT},
-        base::BindOnce(
-            [](const base::FilePath& dir) { base::DeletePathRecursively(dir); },
-            partition->GetPath().Append(kAppCacheDirname)));
   }
 
   // Check first to avoid memory leak in unittests.

content/browser/storage_partition_impl_map_unittest.cc

@@ -9,14 +9,11 @@
 
 #include "base/files/file_util.h"
 #include "base/run_loop.h"
-#include "base/test/scoped_feature_list.h"
 #include "content/public/browser/browser_thread.h"
-#include "content/public/common/content_constants.h"
 #include "content/public/test/browser_task_environment.h"
 #include "content/public/test/test_browser_context.h"
 #include "content/public/test/test_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
-#include "third_party/blink/public/common/features.h"
 
 namespace content {
 
@@ -49,48 +46,4 @@ TEST(StoragePartitionImplMapTest, GarbageCollect) {
   EXPECT_FALSE(base::PathExists(inactive_path));
 }
 
-TEST(StoragePartitionImplMapTest, AppCacheCleanup) {
-  const auto kOnDiskConfig = content::StoragePartitionConfig::Create(
-      "foo", /*partition_name=*/"", /*in_memory=*/false);
-
-  base::test::ScopedFeatureList f;
-  f.InitAndDisableFeature(blink::features::kAppCache);
-  BrowserTaskEnvironment task_environment;
-  TestBrowserContext browser_context;
-  base::FilePath appcache_path;
-
-  {
-    base::RunLoop run_loop;
-    // Creating the partition in the map also does the deletion, so
-    // create it once, so we can find out what path the partition
-    // with this name is.
-    StoragePartitionImplMap map(&browser_context);
-
-    auto* partition = map.Get(kOnDiskConfig, true);
-    appcache_path = partition->GetPath().Append(kAppCacheDirname);
-
-    base::ThreadPool::PostTask(FROM_HERE, run_loop.QuitClosure());
-    run_loop.Run();
-  }
-
-  // Create an AppCache directory that would have existed.
-  EXPECT_FALSE(base::PathExists(appcache_path));
-  EXPECT_TRUE(base::CreateDirectory(appcache_path));
-
-  {
-    base::RunLoop run_loop;
-    StoragePartitionImplMap map(&browser_context);
-    auto* partition = map.Get(kOnDiskConfig, true);
-
-    ASSERT_EQ(appcache_path, partition->GetPath().Append(kAppCacheDirname));
-
-    base::ThreadPool::PostTask(FROM_HERE, run_loop.QuitClosure());
-    run_loop.Run();
-
-    // Verify that creating this partition deletes any AppCache directory it may
-    // have had.
-    EXPECT_FALSE(base::PathExists(appcache_path));
-  }
-}
-
 }  // namespace content

third_party/blink/common/features.cc

@@ -581,8 +581,7 @@ const base::FeatureParam<DelayAsyncScriptDelayType>
 
 // The AppCache feature is a kill-switch for the entire AppCache feature,
 // both backend and API.  If disabled, then it will turn off the backend and
-// api, regardless of the presence of valid origin trial tokens.  Disabling
-// AppCache will also delete any AppCache data from the profile directory.
+// api, regardless of the presence of valid origin trial tokens.
 const base::Feature kAppCache{"AppCache", base::FEATURE_ENABLED_BY_DEFAULT};
 // If AppCacheRequireOriginTrial is enabled, then the AppCache backend in the
 // browser will require origin trial tokens in order to load or store manifests