content/browser/storage_partition_impl_map.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/storage_partition_impl_map.h"
   6
   7 #include "base/bind.h"
   8 #include "base/callback.h"
   9 #include "base/files/file_enumerator.h"
  10 #include "base/files/file_path.h"
  11 #include "base/files/file_util.h"
  12 #include "base/stl_util.h"
  13 #include "base/strings/string_number_conversions.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/strings/stringprintf.h"
  16 #include "base/threading/sequenced_worker_pool.h"
  17 #include "content/browser/appcache/chrome_appcache_service.h"
  18 #include "content/browser/fileapi/browser_file_system_helper.h"
  19 #include "content/browser/fileapi/chrome_blob_storage_context.h"
  20 #include "content/browser/loader/resource_request_info_impl.h"
  21 #include "content/browser/resource_context_impl.h"
  22 #include "content/browser/service_worker/service_worker_request_handler.h"
  23 #include "content/browser/storage_partition_impl.h"
  24 #include "content/browser/streams/stream.h"
  25 #include "content/browser/streams/stream_context.h"
  26 #include "content/browser/streams/stream_registry.h"
  27 #include "content/browser/streams/stream_url_request_job.h"
  28 #include "content/browser/webui/url_data_manager_backend.h"
  29 #include "content/public/browser/browser_context.h"
  30 #include "content/public/browser/browser_thread.h"
  31 #include "content/public/browser/content_browser_client.h"
  32 #include "content/public/browser/storage_partition.h"
  33 #include "content/public/common/content_constants.h"
  34 #include "content/public/common/url_constants.h"
  35 #include "crypto/sha2.h"
  36 #include "net/url_request/url_request_context.h"
  37 #include "net/url_request/url_request_context_getter.h"
  38 #include "webkit/browser/blob/blob_storage_context.h"
  39 #include "webkit/browser/blob/blob_url_request_job_factory.h"
  40 #include "webkit/browser/fileapi/file_system_url_request_job_factory.h"
  41 #include "webkit/common/blob/blob_data.h"
  42
  43 using storage::FileSystemContext;
  44 using storage::BlobStorageContext;
  45
  46 namespace content {
  47
  48 namespace {
  49
  50 // A derivative that knows about Streams too.
  51 class BlobProtocolHandler : public net::URLRequestJobFactory::ProtocolHandler {
  52  public:
  53   BlobProtocolHandler(ChromeBlobStorageContext* blob_storage_context,
  54                       StreamContext* stream_context,
  55                       storage::FileSystemContext* file_system_context)
  56       : blob_storage_context_(blob_storage_context),
  57         stream_context_(stream_context),
  58         file_system_context_(file_system_context) {}
  59
  60   virtual ~BlobProtocolHandler() {
  61   }
  62
  63   virtual net::URLRequestJob* MaybeCreateJob(
  64       net::URLRequest* request,
  65       net::NetworkDelegate* network_delegate) const OVERRIDE {
  66     scoped_refptr<Stream> stream =
  67         stream_context_->registry()->GetStream(request->url());
  68     if (stream.get())
  69       return new StreamURLRequestJob(request, network_delegate, stream);
  70
  71     if (!blob_protocol_handler_) {
  72       // Construction is deferred because 'this' is constructed on
  73       // the main thread but we want blob_protocol_handler_ constructed
  74       // on the IO thread.
  75       blob_protocol_handler_.reset(new storage::BlobProtocolHandler(
  76           blob_storage_context_->context(),
  77           file_system_context_.get(),
  78           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE)
  79               .get()));
  80     }
  81     return blob_protocol_handler_->MaybeCreateJob(request, network_delegate);
  82   }
  83
  84  private:
  85   const scoped_refptr<ChromeBlobStorageContext> blob_storage_context_;
  86   const scoped_refptr<StreamContext> stream_context_;
  87   const scoped_refptr<storage::FileSystemContext> file_system_context_;
  88   mutable scoped_ptr<storage::BlobProtocolHandler> blob_protocol_handler_;
  89   DISALLOW_COPY_AND_ASSIGN(BlobProtocolHandler);
  90 };
  91
  92 // These constants are used to create the directory structure under the profile
  93 // where renderers with a non-default storage partition keep their persistent
  94 // state. This will contain a set of directories that partially mirror the
  95 // directory structure of BrowserContext::GetPath().
  96 //
  97 // The kStoragePartitionDirname contains an extensions directory which is
  98 // further partitioned by extension id, followed by another level of directories
  99 // for the "default" extension storage partition and one directory for each
 100 // persistent partition used by a webview tag. Example:
 101 //
 102 //   Storage/ext/ABCDEF/def
 103 //   Storage/ext/ABCDEF/hash(partition name)
 104 //
 105 // The code in GetStoragePartitionPath() constructs these path names.
 106 //
 107 // TODO(nasko): Move extension related path code out of content.
 108 const base::FilePath::CharType kStoragePartitionDirname[] =
 109     FILE_PATH_LITERAL("Storage");
 110 const base::FilePath::CharType kExtensionsDirname[] =
 111     FILE_PATH_LITERAL("ext");
 112 const base::FilePath::CharType kDefaultPartitionDirname[] =
 113     FILE_PATH_LITERAL("def");
 114 const base::FilePath::CharType kTrashDirname[] =
 115     FILE_PATH_LITERAL("trash");
 116
 117 // Because partition names are user specified, they can be arbitrarily long
 118 // which makes them unsuitable for paths names. We use a truncation of a
 119 // SHA256 hash to perform a deterministic shortening of the string. The
 120 // kPartitionNameHashBytes constant controls the length of the truncation.
 121 // We use 6 bytes, which gives us 99.999% reliability against collisions over
 122 // 1 million partition domains.
 123 //
 124 // Analysis:
 125 // We assume that all partition names within one partition domain are
 126 // controlled by the the same entity. Thus there is no chance for adverserial
 127 // attack and all we care about is accidental collision. To get 5 9s over
 128 // 1 million domains, we need the probability of a collision in any one domain
 129 // to be
 130 //
 131 //    p < nroot(1000000, .99999) ~= 10^-11
 132 //
 133 // We use the following birthday attack approximation to calculate the max
 134 // number of unique names for this probability:
 135 //
 136 //    n(p,H) = sqrt(2*H * ln(1/(1-p)))
 137 //
 138 // For a 6-byte hash, H = 2^(6*8).  n(10^-11, H) ~= 75
 139 //
 140 // An average partition domain is likely to have less than 10 unique
 141 // partition names which is far lower than 75.
 142 //
 143 // Note, that for 4 9s of reliability, the limit is 237 partition names per
 144 // partition domain.
 145 const int kPartitionNameHashBytes = 6;
 146
 147 // Needed for selecting all files in ObliterateOneDirectory() below.
 148 #if defined(OS_POSIX)
 149 const int kAllFileTypes = base::FileEnumerator::FILES |
 150                           base::FileEnumerator::DIRECTORIES |
 151                           base::FileEnumerator::SHOW_SYM_LINKS;
 152 #else
 153 const int kAllFileTypes = base::FileEnumerator::FILES |
 154                           base::FileEnumerator::DIRECTORIES;
 155 #endif
 156
 157 base::FilePath GetStoragePartitionDomainPath(
 158     const std::string& partition_domain) {
 159   CHECK(base::IsStringUTF8(partition_domain));
 160
 161   return base::FilePath(kStoragePartitionDirname).Append(kExtensionsDirname)
 162       .Append(base::FilePath::FromUTF8Unsafe(partition_domain));
 163 }
 164
 165 // Helper function for doing a depth-first deletion of the data on disk.
 166 // Examines paths directly in |current_dir| (no recursion) and tries to
 167 // delete from disk anything that is in, or isn't a parent of something in
 168 // |paths_to_keep|. Paths that need further expansion are added to
 169 // |paths_to_consider|.
 170 void ObliterateOneDirectory(const base::FilePath& current_dir,
 171                             const std::vector<base::FilePath>& paths_to_keep,
 172                             std::vector<base::FilePath>* paths_to_consider) {
 173   CHECK(current_dir.IsAbsolute());
 174
 175   base::FileEnumerator enumerator(current_dir, false, kAllFileTypes);
 176   for (base::FilePath to_delete = enumerator.Next(); !to_delete.empty();
 177        to_delete = enumerator.Next()) {
 178     // Enum tracking which of the 3 possible actions to take for |to_delete|.
 179     enum { kSkip, kEnqueue, kDelete } action = kDelete;
 180
 181     for (std::vector<base::FilePath>::const_iterator to_keep =
 182              paths_to_keep.begin();
 183          to_keep != paths_to_keep.end();
 184          ++to_keep) {
 185       if (to_delete == *to_keep) {
 186         action = kSkip;
 187         break;
 188       } else if (to_delete.IsParent(*to_keep)) {
 189         // |to_delete| contains a path to keep. Add to stack for further
 190         // processing.
 191         action = kEnqueue;
 192         break;
 193       }
 194     }
 195
 196     switch (action) {
 197       case kDelete:
 198         base::DeleteFile(to_delete, true);
 199         break;
 200
 201       case kEnqueue:
 202         paths_to_consider->push_back(to_delete);
 203         break;
 204
 205       case kSkip:
 206         break;
 207     }
 208   }
 209 }
 210
 211 // Synchronously attempts to delete |unnormalized_root|, preserving only
 212 // entries in |paths_to_keep|. If there are no entries in |paths_to_keep| on
 213 // disk, then it completely removes |unnormalized_root|. All paths must be
 214 // absolute paths.
 215 void BlockingObliteratePath(
 216     const base::FilePath& unnormalized_browser_context_root,
 217     const base::FilePath& unnormalized_root,
 218     const std::vector<base::FilePath>& paths_to_keep,
 219     const scoped_refptr<base::TaskRunner>& closure_runner,
 220     const base::Closure& on_gc_required) {
 221   // Early exit required because MakeAbsoluteFilePath() will fail on POSIX
 222   // if |unnormalized_root| does not exist. This is safe because there is
 223   // nothing to do in this situation anwyays.
 224   if (!base::PathExists(unnormalized_root)) {
 225     return;
 226   }
 227
 228   // Never try to obliterate things outside of the browser context root or the
 229   // browser context root itself. Die hard.
 230   base::FilePath root = base::MakeAbsoluteFilePath(unnormalized_root);
 231   base::FilePath browser_context_root =
 232       base::MakeAbsoluteFilePath(unnormalized_browser_context_root);
 233   CHECK(!root.empty());
 234   CHECK(!browser_context_root.empty());
 235   CHECK(browser_context_root.IsParent(root) && browser_context_root != root);
 236
 237   // Reduce |paths_to_keep| set to those under the root and actually on disk.
 238   std::vector<base::FilePath> valid_paths_to_keep;
 239   for (std::vector<base::FilePath>::const_iterator it = paths_to_keep.begin();
 240        it != paths_to_keep.end();
 241        ++it) {
 242     if (root.IsParent(*it) && base::PathExists(*it))
 243       valid_paths_to_keep.push_back(*it);
 244   }
 245
 246   // If none of the |paths_to_keep| are valid anymore then we just whack the
 247   // root and be done with it.  Otherwise, signal garbage collection and do
 248   // a best-effort delete of the on-disk structures.
 249   if (valid_paths_to_keep.empty()) {
 250     base::DeleteFile(root, true);
 251     return;
 252   }
 253   closure_runner->PostTask(FROM_HERE, on_gc_required);
 254
 255   // Otherwise, start at the root and delete everything that is not in
 256   // |valid_paths_to_keep|.
 257   std::vector<base::FilePath> paths_to_consider;
 258   paths_to_consider.push_back(root);
 259   while(!paths_to_consider.empty()) {
 260     base::FilePath path = paths_to_consider.back();
 261     paths_to_consider.pop_back();
 262     ObliterateOneDirectory(path, valid_paths_to_keep, &paths_to_consider);
 263   }
 264 }
 265
 266 // Ensures each path in |active_paths| is a direct child of storage_root.
 267 void NormalizeActivePaths(const base::FilePath& storage_root,
 268                           base::hash_set<base::FilePath>* active_paths) {
 269   base::hash_set<base::FilePath> normalized_active_paths;
 270
 271   for (base::hash_set<base::FilePath>::iterator iter = active_paths->begin();
 272        iter != active_paths->end(); ++iter) {
 273     base::FilePath relative_path;
 274     if (!storage_root.AppendRelativePath(*iter, &relative_path))
 275       continue;
 276
 277     std::vector<base::FilePath::StringType> components;
 278     relative_path.GetComponents(&components);
 279
 280     DCHECK(!relative_path.empty());
 281     normalized_active_paths.insert(storage_root.Append(components.front()));
 282   }
 283
 284   active_paths->swap(normalized_active_paths);
 285 }
 286
 287 // Deletes all entries inside the |storage_root| that are not in the
 288 // |active_paths|.  Deletion is done in 2 steps:
 289 //
 290 //   (1) Moving all garbage collected paths into a trash directory.
 291 //   (2) Asynchronously deleting the trash directory.
 292 //
 293 // The deletion is asynchronous because after (1) completes, calling code can
 294 // safely continue to use the paths that had just been garbage collected
 295 // without fear of race conditions.
 296 //
 297 // This code also ignores failed moves rather than attempting a smarter retry.
 298 // Moves shouldn't fail here unless there is some out-of-band error (eg.,
 299 // FS corruption). Retry logic is dangerous in the general case because
 300 // there is not necessarily a guaranteed case where the logic may succeed.
 301 //
 302 // This function is still named BlockingGarbageCollect() because it does
 303 // execute a few filesystem operations synchronously.
 304 void BlockingGarbageCollect(
 305     const base::FilePath& storage_root,
 306     const scoped_refptr<base::TaskRunner>& file_access_runner,
 307     scoped_ptr<base::hash_set<base::FilePath> > active_paths) {
 308   CHECK(storage_root.IsAbsolute());
 309
 310   NormalizeActivePaths(storage_root, active_paths.get());
 311
 312   base::FileEnumerator enumerator(storage_root, false, kAllFileTypes);
 313   base::FilePath trash_directory;
 314   if (!base::CreateTemporaryDirInDir(storage_root, kTrashDirname,
 315                                      &trash_directory)) {
 316     // Unable to continue without creating the trash directory so give up.
 317     return;
 318   }
 319   for (base::FilePath path = enumerator.Next(); !path.empty();
 320        path = enumerator.Next()) {
 321     if (active_paths->find(path) == active_paths->end() &&
 322         path != trash_directory) {
 323       // Since |trash_directory| is unique for each run of this function there
 324       // can be no colllisions on the move.
 325       base::Move(path, trash_directory.Append(path.BaseName()));
 326     }
 327   }
 328
 329   file_access_runner->PostTask(
 330       FROM_HERE,
 331       base::Bind(base::IgnoreResult(&base::DeleteFile), trash_directory, true));
 332 }
 333
 334 }  // namespace
 335
 336 // static
 337 base::FilePath StoragePartitionImplMap::GetStoragePartitionPath(
 338     const std::string& partition_domain,
 339     const std::string& partition_name) {
 340   if (partition_domain.empty())
 341     return base::FilePath();
 342
 343   base::FilePath path = GetStoragePartitionDomainPath(partition_domain);
 344
 345   // TODO(ajwong): Mangle in-memory into this somehow, either by putting
 346   // it into the partition_name, or by manually adding another path component
 347   // here.  Otherwise, it's possible to have an in-memory StoragePartition and
 348   // a persistent one that return the same FilePath for GetPath().
 349   if (!partition_name.empty()) {
 350     // For analysis of why we can ignore collisions, see the comment above
 351     // kPartitionNameHashBytes.
 352     char buffer[kPartitionNameHashBytes];
 353     crypto::SHA256HashString(partition_name, &buffer[0],
 354                              sizeof(buffer));
 355     return path.AppendASCII(base::HexEncode(buffer, sizeof(buffer)));
 356   }
 357
 358   return path.Append(kDefaultPartitionDirname);
 359 }
 360
 361 StoragePartitionImplMap::StoragePartitionImplMap(
 362     BrowserContext* browser_context)
 363     : browser_context_(browser_context),
 364       resource_context_initialized_(false) {
 365   // Doing here instead of initializer list cause it's just too ugly to read.
 366   base::SequencedWorkerPool* blocking_pool = BrowserThread::GetBlockingPool();
 367   file_access_runner_ =
 368       blocking_pool->GetSequencedTaskRunner(blocking_pool->GetSequenceToken());
 369 }
 370
 371 StoragePartitionImplMap::~StoragePartitionImplMap() {
 372   STLDeleteContainerPairSecondPointers(partitions_.begin(),
 373                                        partitions_.end());
 374 }
 375
 376 StoragePartitionImpl* StoragePartitionImplMap::Get(
 377     const std::string& partition_domain,
 378     const std::string& partition_name,
 379     bool in_memory) {
 380   // Find the previously created partition if it's available.
 381   StoragePartitionConfig partition_config(
 382       partition_domain, partition_name, in_memory);
 383
 384   PartitionMap::const_iterator it = partitions_.find(partition_config);
 385   if (it != partitions_.end())
 386     return it->second;
 387
 388   base::FilePath partition_path =
 389       browser_context_->GetPath().Append(
 390           GetStoragePartitionPath(partition_domain, partition_name));
 391   StoragePartitionImpl* partition =
 392       StoragePartitionImpl::Create(browser_context_, in_memory,
 393                                    partition_path);
 394   partitions_[partition_config] = partition;
 395
 396   ChromeBlobStorageContext* blob_storage_context =
 397       ChromeBlobStorageContext::GetFor(browser_context_);
 398   StreamContext* stream_context = StreamContext::GetFor(browser_context_);
 399   ProtocolHandlerMap protocol_handlers;
 400   protocol_handlers[url::kBlobScheme] =
 401       linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
 402           new BlobProtocolHandler(blob_storage_context,
 403                                   stream_context,
 404                                   partition->GetFileSystemContext()));
 405   protocol_handlers[url::kFileSystemScheme] =
 406       linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
 407           CreateFileSystemProtocolHandler(partition_domain,
 408                                           partition->GetFileSystemContext()));
 409   protocol_handlers[kChromeUIScheme] =
 410       linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
 411           URLDataManagerBackend::CreateProtocolHandler(
 412               browser_context_->GetResourceContext(),
 413               browser_context_->IsOffTheRecord(),
 414               partition->GetAppCacheService(),
 415               blob_storage_context));
 416   std::vector<std::string> additional_webui_schemes;
 417   GetContentClient()->browser()->GetAdditionalWebUISchemes(
 418       &additional_webui_schemes);
 419   for (std::vector<std::string>::const_iterator it =
 420            additional_webui_schemes.begin();
 421        it != additional_webui_schemes.end();
 422        ++it) {
 423     protocol_handlers[*it] =
 424         linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
 425             URLDataManagerBackend::CreateProtocolHandler(
 426                 browser_context_->GetResourceContext(),
 427                 browser_context_->IsOffTheRecord(),
 428                 partition->GetAppCacheService(),
 429                 blob_storage_context));
 430   }
 431   protocol_handlers[kChromeDevToolsScheme] =
 432       linked_ptr<net::URLRequestJobFactory::ProtocolHandler>(
 433           CreateDevToolsProtocolHandler(browser_context_->GetResourceContext(),
 434                                         browser_context_->IsOffTheRecord()));
 435
 436   URLRequestInterceptorScopedVector request_interceptors;
 437   request_interceptors.push_back(
 438       ServiceWorkerRequestHandler::CreateInterceptor().release());
 439
 440   // These calls must happen after StoragePartitionImpl::Create().
 441   if (partition_domain.empty()) {
 442     partition->SetURLRequestContext(
 443         GetContentClient()->browser()->CreateRequestContext(
 444             browser_context_,
 445             &protocol_handlers,
 446             request_interceptors.Pass()));
 447   } else {
 448     partition->SetURLRequestContext(
 449         GetContentClient()->browser()->CreateRequestContextForStoragePartition(
 450             browser_context_,
 451             partition->GetPath(),
 452             in_memory,
 453             &protocol_handlers,
 454             request_interceptors.Pass()));
 455   }
 456   partition->SetMediaURLRequestContext(
 457       partition_domain.empty() ?
 458       browser_context_->GetMediaRequestContext() :
 459       browser_context_->GetMediaRequestContextForStoragePartition(
 460           partition->GetPath(), in_memory));
 461
 462   PostCreateInitialization(partition, in_memory);
 463
 464   return partition;
 465 }
 466
 467 void StoragePartitionImplMap::AsyncObliterate(
 468     const GURL& site,
 469     const base::Closure& on_gc_required) {
 470   // This method should avoid creating any StoragePartition (which would
 471   // create more open file handles) so that it can delete as much of the
 472   // data off disk as possible.
 473   std::string partition_domain;
 474   std::string partition_name;
 475   bool in_memory = false;
 476   GetContentClient()->browser()->GetStoragePartitionConfigForSite(
 477       browser_context_, site, false, &partition_domain,
 478       &partition_name, &in_memory);
 479
 480   // Find the active partitions for the domain. Because these partitions are
 481   // active, it is not possible to just delete the directories that contain
 482   // the backing data structures without causing the browser to crash. Instead,
 483   // of deleteing the directory, we tell each storage context later to
 484   // remove any data they have saved. This will leave the directory structure
 485   // intact but it will only contain empty databases.
 486   std::vector<StoragePartitionImpl*> active_partitions;
 487   std::vector<base::FilePath> paths_to_keep;
 488   for (PartitionMap::const_iterator it = partitions_.begin();
 489        it != partitions_.end();
 490        ++it) {
 491     const StoragePartitionConfig& config = it->first;
 492     if (config.partition_domain == partition_domain) {
 493       it->second->ClearData(
 494           // All except shader cache.
 495           ~StoragePartition::REMOVE_DATA_MASK_SHADER_CACHE,
 496           StoragePartition::QUOTA_MANAGED_STORAGE_MASK_ALL,
 497           GURL(),
 498           StoragePartition::OriginMatcherFunction(),
 499           base::Time(), base::Time::Max(),
 500           base::Bind(&base::DoNothing));
 501       if (!config.in_memory) {
 502         paths_to_keep.push_back(it->second->GetPath());
 503       }
 504     }
 505   }
 506
 507   // Start a best-effort delete of the on-disk storage excluding paths that are
 508   // known to still be in use. This is to delete any previously created
 509   // StoragePartition state that just happens to not have been used during this
 510   // run of the browser.
 511   base::FilePath domain_root = browser_context_->GetPath().Append(
 512       GetStoragePartitionDomainPath(partition_domain));
 513
 514   BrowserThread::PostBlockingPoolTask(
 515       FROM_HERE,
 516       base::Bind(&BlockingObliteratePath, browser_context_->GetPath(),
 517                  domain_root, paths_to_keep,
 518                  base::MessageLoopProxy::current(), on_gc_required));
 519 }
 520
 521 void StoragePartitionImplMap::GarbageCollect(
 522     scoped_ptr<base::hash_set<base::FilePath> > active_paths,
 523     const base::Closure& done) {
 524   // Include all paths for current StoragePartitions in the active_paths since
 525   // they cannot be deleted safely.
 526   for (PartitionMap::const_iterator it = partitions_.begin();
 527        it != partitions_.end();
 528        ++it) {
 529     const StoragePartitionConfig& config = it->first;
 530     if (!config.in_memory)
 531       active_paths->insert(it->second->GetPath());
 532   }
 533
 534   // Find the directory holding the StoragePartitions and delete everything in
 535   // there that isn't considered active.
 536   base::FilePath storage_root = browser_context_->GetPath().Append(
 537       GetStoragePartitionDomainPath(std::string()));
 538   file_access_runner_->PostTaskAndReply(
 539       FROM_HERE,
 540       base::Bind(&BlockingGarbageCollect, storage_root,
 541                  file_access_runner_,
 542                  base::Passed(&active_paths)),
 543       done);
 544 }
 545
 546 void StoragePartitionImplMap::ForEach(
 547     const BrowserContext::StoragePartitionCallback& callback) {
 548   for (PartitionMap::const_iterator it = partitions_.begin();
 549        it != partitions_.end();
 550        ++it) {
 551     callback.Run(it->second);
 552   }
 553 }
 554
 555 void StoragePartitionImplMap::PostCreateInitialization(
 556     StoragePartitionImpl* partition,
 557     bool in_memory) {
 558   // TODO(ajwong): ResourceContexts no longer have any storage related state.
 559   // We should move this into a place where it is called once per
 560   // BrowserContext creation rather than piggybacking off the default context
 561   // creation.
 562   // Note: moving this into Get() before partitions_[] is set causes reentrency.
 563   if (!resource_context_initialized_) {
 564     resource_context_initialized_ = true;
 565     InitializeResourceContext(browser_context_);
 566   }
 567
 568   // Check first to avoid memory leak in unittests.
 569   if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
 570     BrowserThread::PostTask(
 571         BrowserThread::IO, FROM_HERE,
 572         base::Bind(&ChromeAppCacheService::InitializeOnIOThread,
 573                    partition->GetAppCacheService(),
 574                    in_memory ? base::FilePath() :
 575                        partition->GetPath().Append(kAppCacheDirname),
 576                    browser_context_->GetResourceContext(),
 577                    make_scoped_refptr(partition->GetURLRequestContext()),
 578                    make_scoped_refptr(
 579                        browser_context_->GetSpecialStoragePolicy())));
 580
 581     BrowserThread::PostTask(
 582         BrowserThread::IO,
 583         FROM_HERE,
 584         base::Bind(&ServiceWorkerContextWrapper::SetBlobParametersForCache,
 585                    partition->GetServiceWorkerContext(),
 586                    make_scoped_refptr(partition->GetURLRequestContext()),
 587                    make_scoped_refptr(
 588                        ChromeBlobStorageContext::GetFor(browser_context_))));
 589
 590     // We do not call InitializeURLRequestContext() for media contexts because,
 591     // other than the HTTP cache, the media contexts share the same backing
 592     // objects as their associated "normal" request context.  Thus, the previous
 593     // call serves to initialize the media request context for this storage
 594     // partition as well.
 595   }
 596 }
 597
 598 }  // namespace content