Add FileChangeObserver to track changes in local file system

BUG=146290,146317
TEST=LocalFileSystemOperationTest.*, ObfuscatedFileUtilTest.*

Review URL: https://chromiumcodereview.appspot.com/10909060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@155632 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 403 insertions, 8 deletions

diff --git a/webkit/fileapi/file_observers.h b/webkit/fileapi/file_observers.h
index 2022b81..8b64161 100644
--- a/webkit/fileapi/file_observers.h
+++ b/webkit/fileapi/file_observers.h
@@ -46,6 +46,25 @@ class FILEAPI_EXPORT FileAccessObserver {
   virtual void OnAccess(const FileSystemURL& url) = 0;
 };
 
+// An abstract interface to observe file changes.
+// Each method of this class is called once per file/directory is created,
+// removed or modified.  For recursive operations each method is called for
+// each subdirectory/subfile.  Currently ChangeObserver is only supported
+// by the local sandbox file system.
+class FILEAPI_EXPORT FileChangeObserver {
+ public:
+  virtual ~FileChangeObserver() {}
+
+  virtual void OnCreateFile(const FileSystemURL& url) = 0;
+  virtual void OnCreateFileFrom(const FileSystemURL& url,
+                                const FileSystemURL& src) = 0;
+  virtual void OnRemoveFile(const FileSystemURL& url) = 0;
+  virtual void OnModifyFile(const FileSystemURL& url) = 0;
+
+  virtual void OnCreateDirectory(const FileSystemURL& url) = 0;
+  virtual void OnRemoveDirectory(const FileSystemURL& url) = 0;
+};
+
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_FILE_OBSERVERS_H_
diff --git a/webkit/fileapi/file_system_operation_context.h b/webkit/fileapi/file_system_operation_context.h
index f1dbda2..89b109c 100644
--- a/webkit/fileapi/file_system_operation_context.h
+++ b/webkit/fileapi/file_system_operation_context.h
@@ -65,6 +65,11 @@ class FILEAPI_EXPORT_PRIVATE FileSystemOperationContext {
     return media_path_filter_;
   }
 
+  void set_change_observers(const ChangeObserverList& list) {
+    change_observers_ = list;
+  }
+  ChangeObserverList* change_observers() { return &change_observers_; }
+
   void set_access_observers(const AccessObserverList& list) {
     access_observers_ = list;
   }
@@ -83,6 +88,7 @@ class FILEAPI_EXPORT_PRIVATE FileSystemOperationContext {
   MediaPathFilter* media_path_filter_;
 
   AccessObserverList access_observers_;
+  ChangeObserverList change_observers_;
   UpdateObserverList update_observers_;
 
 #if defined(SUPPORT_MEDIA_FILESYSTEM)
diff --git a/webkit/fileapi/local_file_system_operation.h b/webkit/fileapi/local_file_system_operation.h
index b005b64..10dd19d 100644
--- a/webkit/fileapi/local_file_system_operation.h
+++ b/webkit/fileapi/local_file_system_operation.h
@@ -115,8 +115,8 @@ class FILEAPI_EXPORT LocalFileSystemOperation
   friend class TestMountPointProvider;
   friend class chromeos::CrosMountPointProvider;
 
-  friend class FileSystemOperationTest;
-  friend class FileSystemOperationWriteTest;
+  friend class LocalFileSystemOperationTest;
+  friend class LocalFileSystemOperationWriteTest;
   friend class FileWriterDelegateTest;
   friend class FileSystemQuotaTest;
   friend class LocalFileSystemTestOriginHelper;
@@ -129,6 +129,10 @@ class FILEAPI_EXPORT LocalFileSystemOperation
     return operation_context_->file_system_context();
   }
 
+  FileSystemOperationContext* operation_context() const {
+    return operation_context_.get();
+  }
+
   // The unit tests that need to specify and control the lifetime of the
   // file_util on their own should call this before performing the actual
   // operation. If it is given it will not be overwritten by the class.
diff --git a/webkit/fileapi/local_file_system_operation_unittest.cc b/webkit/fileapi/local_file_system_operation_unittest.cc
index d786406..d2aa935 100644
--- a/webkit/fileapi/local_file_system_operation_unittest.cc
+++ b/webkit/fileapi/local_file_system_operation_unittest.cc
@@ -21,6 +21,7 @@
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/file_util_helper.h"
 #include "webkit/fileapi/local_file_system_test_helper.h"
+#include "webkit/fileapi/mock_file_change_observer.h"
 #include "webkit/quota/quota_manager.h"
 
 using quota::QuotaClient;
@@ -169,6 +170,7 @@ class LocalFileSystemOperationTest
       : status_(kFileOperationStatusNotSet),
         next_unique_path_suffix_(0) {
     EXPECT_TRUE(base_.CreateUniqueTempDir());
+    change_observers_ = MockFileChangeObserver::CreateList(&change_observer_);
   }
 
   LocalFileSystemOperation* operation();
@@ -198,6 +200,14 @@ class LocalFileSystemOperationTest
     return test_helper_.file_util();
   }
 
+  const ChangeObserverList& change_observers() const {
+    return change_observers_;
+  }
+
+  MockFileChangeObserver* change_observer() {
+    return &change_observer_;
+  }
+
   FileSystemOperationContext* NewContext() {
     FileSystemOperationContext* context = test_helper_.NewOperationContext();
     // Grant enough quota for all test cases.
@@ -385,6 +395,9 @@ class LocalFileSystemOperationTest
   scoped_refptr<QuotaManager> quota_manager_;
   scoped_refptr<QuotaManagerProxy> quota_manager_proxy_;
 
+  MockFileChangeObserver change_observer_;
+  ChangeObserverList change_observers_;
+
   int next_unique_path_suffix_;
 
   DISALLOW_COPY_AND_ASSIGN(LocalFileSystemOperationTest);
@@ -410,15 +423,19 @@ void LocalFileSystemOperationTest::TearDown() {
 }
 
 LocalFileSystemOperation* LocalFileSystemOperationTest::operation() {
-  return test_helper_.NewOperation();
+  LocalFileSystemOperation* operation = test_helper_.NewOperation();
+  operation->operation_context()->set_change_observers(change_observers());
+  return operation;
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveFailureSrcDoesntExist) {
   FileSystemURL src(URLForPath(FilePath(FILE_PATH_LITERAL("a"))));
   FileSystemURL dest(URLForPath(FilePath(FILE_PATH_LITERAL("b"))));
+  change_observer()->ResetCount();
   operation()->Move(src, dest, RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveFailureContainsPath) {
@@ -428,6 +445,7 @@ TEST_F(LocalFileSystemOperationTest, TestMoveFailureContainsPath) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveFailureSrcDirExistsDestFile) {
@@ -440,6 +458,7 @@ TEST_F(LocalFileSystemOperationTest, TestMoveFailureSrcDirExistsDestFile) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest,
@@ -453,6 +472,7 @@ TEST_F(LocalFileSystemOperationTest,
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_EMPTY, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveFailureSrcFileExistsDestDir) {
@@ -465,6 +485,7 @@ TEST_F(LocalFileSystemOperationTest, TestMoveFailureSrcFileExistsDestDir) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveFailureDestParentDoesntExist) {
@@ -477,6 +498,7 @@ TEST_F(LocalFileSystemOperationTest, TestMoveFailureDestParentDoesntExist) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcFileAndOverwrite) {
@@ -491,6 +513,10 @@ TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcFileAndOverwrite) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(FileExists(dest_file_path));
 
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
+
   // Move is considered 'write' access (for both side), and won't be counted
   // as read access.
   EXPECT_EQ(0, quota_manager_proxy()->storage_accessed_count());
@@ -507,6 +533,10 @@ TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcFileAndNew) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(FileExists(dest_file_path));
+
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_from_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcDirAndOverwrite) {
@@ -519,6 +549,10 @@ TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcDirAndOverwrite) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_FALSE(DirectoryExists(src_dir_path));
 
+  EXPECT_EQ(2, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
+
   // Make sure we've overwritten but not moved the source under the |dest_dir|.
   EXPECT_TRUE(DirectoryExists(dest_dir_path));
   EXPECT_FALSE(DirectoryExists(
@@ -537,6 +571,10 @@ TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcDirAndNew) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_FALSE(DirectoryExists(src_dir_path));
   EXPECT_TRUE(DirectoryExists(dest_child_dir_path));
+
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcDirRecursive) {
@@ -556,6 +594,12 @@ TEST_F(LocalFileSystemOperationTest, TestMoveSuccessSrcDirRecursive) {
   EXPECT_TRUE(FileExists(dest_dir_path.Append(
       VirtualPath::BaseName(child_dir_path)).Append(
       VirtualPath::BaseName(grandchild_file_path))));
+
+  EXPECT_EQ(3, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_EQ(2, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_file_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_from_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopyFailureSrcDoesntExist) {
@@ -564,6 +608,7 @@ TEST_F(LocalFileSystemOperationTest, TestCopyFailureSrcDoesntExist) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopyFailureContainsPath) {
@@ -573,6 +618,7 @@ TEST_F(LocalFileSystemOperationTest, TestCopyFailureContainsPath) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopyFailureSrcDirExistsDestFile) {
@@ -585,6 +631,7 @@ TEST_F(LocalFileSystemOperationTest, TestCopyFailureSrcDirExistsDestFile) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest,
@@ -598,6 +645,7 @@ TEST_F(LocalFileSystemOperationTest,
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_EMPTY, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopyFailureSrcFileExistsDestDir) {
@@ -610,6 +658,7 @@ TEST_F(LocalFileSystemOperationTest, TestCopyFailureSrcFileExistsDestDir) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopyFailureDestParentDoesntExist) {
@@ -625,6 +674,7 @@ TEST_F(LocalFileSystemOperationTest, TestCopyFailureDestParentDoesntExist) {
                     RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopyFailureByQuota) {
@@ -670,6 +720,9 @@ TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcFileAndOverwrite) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(FileExists(dest_file_path));
   EXPECT_EQ(1, quota_manager_proxy()->storage_accessed_count());
+
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcFileAndNew) {
@@ -684,6 +737,9 @@ TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcFileAndNew) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(FileExists(dest_file_path));
   EXPECT_EQ(1, quota_manager_proxy()->storage_accessed_count());
+
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_from_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcDirAndOverwrite) {
@@ -700,6 +756,10 @@ TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcDirAndOverwrite) {
   EXPECT_FALSE(DirectoryExists(
       dest_dir_path.Append(VirtualPath::BaseName(src_dir_path))));
   EXPECT_EQ(1, quota_manager_proxy()->storage_accessed_count());
+
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcDirAndNew) {
@@ -714,6 +774,9 @@ TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcDirAndNew) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(DirectoryExists(dest_child_dir_path));
   EXPECT_EQ(1, quota_manager_proxy()->storage_accessed_count());
+
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcDirRecursive) {
@@ -734,6 +797,11 @@ TEST_F(LocalFileSystemOperationTest, TestCopySuccessSrcDirRecursive) {
       VirtualPath::BaseName(child_dir_path)).Append(
       VirtualPath::BaseName(grandchild_file_path))));
   EXPECT_EQ(1, quota_manager_proxy()->storage_accessed_count());
+
+  EXPECT_EQ(2, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_from_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateFileFailure) {
@@ -744,6 +812,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateFileFailure) {
                           RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateFileSuccessFileExists) {
@@ -755,6 +824,9 @@ TEST_F(LocalFileSystemOperationTest, TestCreateFileSuccessFileExists) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(FileExists(file_path));
+
+  // The file was already there; did nothing.
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateFileSuccessExclusive) {
@@ -766,6 +838,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateFileSuccessExclusive) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(FileExists(file_path));
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateFileSuccessFileDoesntExist) {
@@ -776,6 +849,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateFileSuccessFileDoesntExist) {
                           RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
 }
 
 TEST_F(LocalFileSystemOperationTest,
@@ -789,6 +863,7 @@ TEST_F(LocalFileSystemOperationTest,
                                RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateDirFailureDirExists) {
@@ -798,6 +873,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateDirFailureDirExists) {
                                RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateDirFailureFileExists) {
@@ -808,6 +884,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateDirFailureFileExists) {
                                RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateDirSuccess) {
@@ -817,6 +894,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateDirSuccess) {
                                RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   // Dir doesn't exist.
   FilePath nonexisting_dir_path(FilePath(
@@ -826,6 +904,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateDirSuccess) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(DirectoryExists(nonexisting_dir_path));
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestCreateDirSuccessExclusive) {
@@ -838,6 +917,8 @@ TEST_F(LocalFileSystemOperationTest, TestCreateDirSuccessExclusive) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_TRUE(DirectoryExists(nonexisting_dir_path));
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestExistsAndMetadataFailure) {
@@ -858,6 +939,7 @@ TEST_F(LocalFileSystemOperationTest, TestExistsAndMetadataFailure) {
                                RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestExistsAndMetadataSuccess) {
@@ -891,6 +973,7 @@ TEST_F(LocalFileSystemOperationTest, TestExistsAndMetadataSuccess) {
   ++read_access;
 
   EXPECT_EQ(read_access, quota_manager_proxy()->storage_accessed_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestTypeMismatchErrors) {
@@ -924,6 +1007,7 @@ TEST_F(LocalFileSystemOperationTest, TestReadDirFailure) {
   MessageLoop::current()->RunAllPending();
   // TODO(kkanetkar) crbug.com/54309 to change the error code.
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestReadDirSuccess) {
@@ -952,6 +1036,7 @@ TEST_F(LocalFileSystemOperationTest, TestReadDirSuccess) {
     }
   }
   EXPECT_EQ(1, quota_manager_proxy()->storage_accessed_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestRemoveFailure) {
@@ -981,6 +1066,7 @@ TEST_F(LocalFileSystemOperationTest, TestRemoveFailure) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_EMPTY,
             status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestRemoveSuccess) {
@@ -993,6 +1079,9 @@ TEST_F(LocalFileSystemOperationTest, TestRemoveSuccess) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_FALSE(DirectoryExists(empty_dir_path));
 
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
+
   // Removing a non-empty directory with recursive flag == true should be ok.
   //      parent_dir
   //       |       |
@@ -1011,6 +1100,10 @@ TEST_F(LocalFileSystemOperationTest, TestRemoveSuccess) {
 
   // Remove is not a 'read' access.
   EXPECT_EQ(0, quota_manager_proxy()->storage_accessed_count());
+
+  EXPECT_EQ(2, change_observer()->get_and_reset_remove_directory_count());
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(LocalFileSystemOperationTest, TestTruncate) {
@@ -1036,6 +1129,9 @@ TEST_F(LocalFileSystemOperationTest, TestTruncate) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
 
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
+
   // Check that its length is now 17 and that it's all zeroes after the test
   // data.
   base::PlatformFileInfo info;
@@ -1057,6 +1153,9 @@ TEST_F(LocalFileSystemOperationTest, TestTruncate) {
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
 
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
+
   // Check that its length is now 3 and that it contains only bits of test data.
   EXPECT_TRUE(file_util::GetFileInfo(PlatformPath(file_path), &info));
   EXPECT_EQ(length, info.size);
@@ -1081,6 +1180,8 @@ TEST_F(LocalFileSystemOperationTest, TestTruncateFailureByQuota) {
   operation()->Truncate(URLForPath(file_path), 10, RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   EXPECT_TRUE(file_util::GetFileInfo(PlatformPath(file_path), &info));
   EXPECT_EQ(10, info.size);
@@ -1088,6 +1189,7 @@ TEST_F(LocalFileSystemOperationTest, TestTruncateFailureByQuota) {
   operation()->Truncate(URLForPath(file_path), 11, RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NO_SPACE, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   EXPECT_TRUE(file_util::GetFileInfo(PlatformPath(file_path), &info));
   EXPECT_EQ(10, info.size);
@@ -1116,6 +1218,7 @@ TEST_F(LocalFileSystemOperationTest, TestTouchFile) {
       RecordStatusCallback());
   MessageLoop::current()->RunAllPending();
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   EXPECT_TRUE(file_util::GetFileInfo(platform_path, &info));
   // We compare as time_t here to lower our resolution, to avoid false
@@ -1146,6 +1249,7 @@ TEST_F(LocalFileSystemOperationTest, TestCreateSnapshotFile) {
   EXPECT_EQ(base::PLATFORM_FILE_OK, status());
   EXPECT_FALSE(info().is_directory);
   EXPECT_EQ(PlatformPath(file_path), path());
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   // The FileSystemOpration implementation does not create a
   // shareable file reference.
diff --git a/webkit/fileapi/mock_file_change_observer.cc b/webkit/fileapi/mock_file_change_observer.cc
new file mode 100644
index 0000000..c358185
--- /dev/null
+++ b/webkit/fileapi/mock_file_change_observer.cc
@@ -0,0 +1,52 @@
+// Copyright (c) 2012 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.
+
+#include "webkit/fileapi/mock_file_change_observer.h"
+
+namespace fileapi {
+
+MockFileChangeObserver::MockFileChangeObserver()
+    : create_file_count_(0),
+      create_file_from_count_(0),
+      remove_file_count_(0),
+      modify_file_count_(0),
+      create_directory_count_(0),
+      remove_directory_count_(0) {}
+
+MockFileChangeObserver::~MockFileChangeObserver() {}
+
+// static
+ChangeObserverList MockFileChangeObserver::CreateList(
+    MockFileChangeObserver* observer) {
+  ChangeObserverList::Source source;
+  source.AddObserver(observer, base::MessageLoopProxy::current());
+  return ChangeObserverList(source);
+}
+
+void MockFileChangeObserver::OnCreateFile(const FileSystemURL& url) {
+  create_file_count_++;
+}
+
+void MockFileChangeObserver::OnCreateFileFrom(const FileSystemURL& url,
+                                              const FileSystemURL& src) {
+  create_file_from_count_++;
+}
+
+void MockFileChangeObserver::OnRemoveFile(const FileSystemURL& url) {
+  remove_file_count_++;
+}
+
+void MockFileChangeObserver::OnModifyFile(const FileSystemURL& url) {
+  modify_file_count_++;
+}
+
+void MockFileChangeObserver::OnCreateDirectory(const FileSystemURL& url) {
+  create_directory_count_++;
+}
+
+void MockFileChangeObserver::OnRemoveDirectory(const FileSystemURL& url) {
+  remove_directory_count_++;
+}
+
+}  // namespace fileapi
diff --git a/webkit/fileapi/mock_file_change_observer.h b/webkit/fileapi/mock_file_change_observer.h
new file mode 100644
index 0000000..81cfad9
--- /dev/null
+++ b/webkit/fileapi/mock_file_change_observer.h
@@ -0,0 +1,103 @@
+// Copyright (c) 2012 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.
+
+#ifndef WEBKIT_FILEAPI_MOCK_FILE_CHANGE_OBSERVER_H_
+#define WEBKIT_FILEAPI_MOCK_FILE_CHANGE_OBSERVER_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "webkit/fileapi/file_observers.h"
+#include "webkit/fileapi/file_system_url.h"
+#include "webkit/fileapi/task_runner_bound_observer_list.h"
+
+namespace fileapi {
+
+// Mock file change observer.
+class MockFileChangeObserver : public FileChangeObserver {
+ public:
+  MockFileChangeObserver();
+  virtual ~MockFileChangeObserver();
+
+  // Creates a ChangeObserverList which only contains given |observer|.
+  static ChangeObserverList CreateList(MockFileChangeObserver* observer);
+
+  // FileChangeObserver overrides.
+  virtual void OnCreateFile(const FileSystemURL& url) OVERRIDE;
+  virtual void OnCreateFileFrom(const FileSystemURL& url,
+                                const FileSystemURL& src) OVERRIDE;
+  virtual void OnRemoveFile(const FileSystemURL& url) OVERRIDE;
+  virtual void OnModifyFile(const FileSystemURL& url) OVERRIDE;
+  virtual void OnCreateDirectory(const FileSystemURL& url) OVERRIDE;
+  virtual void OnRemoveDirectory(const FileSystemURL& url) OVERRIDE;
+
+  void ResetCount() {
+    create_file_count_ = 0;
+    create_file_from_count_ = 0;
+    remove_file_count_ = 0;
+    modify_file_count_ = 0;
+    create_directory_count_ = 0;
+    remove_directory_count_ = 0;
+  }
+
+  bool HasNoChange() const {
+    return create_file_count_ == 0 &&
+           create_file_from_count_ == 0 &&
+           remove_file_count_ == 0 &&
+           modify_file_count_ == 0 &&
+           create_directory_count_ == 0 &&
+           remove_directory_count_ == 0;
+  }
+
+  int create_file_count() const { return create_file_count_; }
+  int create_file_from_count() const { return create_file_from_count_; }
+  int remove_file_count() const { return remove_file_count_; }
+  int modify_file_count() const { return modify_file_count_; }
+  int create_directory_count() const { return create_directory_count_; }
+  int remove_directory_count() const { return remove_directory_count_; }
+
+  int get_and_reset_create_file_count() {
+    int tmp = create_file_count_;
+    create_file_count_ = 0;
+    return tmp;
+  }
+  int get_and_reset_create_file_from_count() {
+    int tmp = create_file_from_count_;
+    create_file_from_count_ = 0;
+    return tmp;
+  }
+  int get_and_reset_remove_file_count() {
+    int tmp = remove_file_count_;
+    remove_file_count_ = 0;
+    return tmp;
+  }
+  int get_and_reset_modify_file_count() {
+    int tmp = modify_file_count_;
+    modify_file_count_ = 0;
+    return tmp;
+  }
+  int get_and_reset_create_directory_count() {
+    int tmp = create_directory_count_;
+    create_directory_count_ = 0;
+    return tmp;
+  }
+  int get_and_reset_remove_directory_count() {
+    int tmp = remove_directory_count_;
+    remove_directory_count_ = 0;
+    return tmp;
+  }
+
+ private:
+  int create_file_count_;
+  int create_file_from_count_;
+  int remove_file_count_;
+  int modify_file_count_;
+  int create_directory_count_;
+  int remove_directory_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(MockFileChangeObserver);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_MOCK_FILE_CHANGE_OBSERVER_H_
diff --git a/webkit/fileapi/obfuscated_file_util.cc b/webkit/fileapi/obfuscated_file_util.cc
index fddf937..1022954 100644
--- a/webkit/fileapi/obfuscated_file_util.cc
+++ b/webkit/fileapi/obfuscated_file_util.cc
@@ -293,6 +293,8 @@ PlatformFileError ObfuscatedFileUtil::CreateOrOpen(
     if (created && base::PLATFORM_FILE_OK == error) {
       *created = true;
       UpdateUsage(context, url, growth);
+      context->change_observers()->Notify(
+          &FileChangeObserver::OnCreateFile, MakeTuple(url));
     }
     return error;
   }
@@ -330,8 +332,11 @@ PlatformFileError ObfuscatedFileUtil::CreateOrOpen(
   }
 
   // If truncating we need to update the usage.
-  if (error == base::PLATFORM_FILE_OK && delta)
+  if (error == base::PLATFORM_FILE_OK && delta) {
     UpdateUsage(context, url, delta);
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnModifyFile, MakeTuple(url));
+  }
   return error;
 }
 
@@ -379,6 +384,8 @@ PlatformFileError ObfuscatedFileUtil::EnsureFileExists(
   if (created && base::PLATFORM_FILE_OK == error) {
     *created = true;
     UpdateUsage(context, url, growth);
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnCreateFile, MakeTuple(url));
   }
   return error;
 }
@@ -436,6 +443,8 @@ PlatformFileError ObfuscatedFileUtil::CreateDirectory(
       return base::PLATFORM_FILE_ERROR_FAILED;
     }
     UpdateUsage(context, url, growth);
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnCreateDirectory, MakeTuple(url));
     if (first) {
       first = false;
       TouchDirectory(db, file_info.parent_id);
@@ -545,8 +554,11 @@ PlatformFileError ObfuscatedFileUtil::Truncate(
   if (!AllocateQuota(context, growth))
     return base::PLATFORM_FILE_ERROR_NO_SPACE;
   error = NativeFileUtil::Truncate(local_path, length);
-  if (error == base::PLATFORM_FILE_OK)
+  if (error == base::PLATFORM_FILE_OK) {
     UpdateUsage(context, url, growth);
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnModifyFile, MakeTuple(url));
+  }
   return error;
 }
 
@@ -695,8 +707,22 @@ PlatformFileError ObfuscatedFileUtil::CopyOrMoveFile(
   if (error != base::PLATFORM_FILE_OK)
     return error;
 
-  if (!copy)
+  if (overwrite) {
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnModifyFile,
+        MakeTuple(dest_url));
+  } else {
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnCreateFileFrom,
+        MakeTuple(dest_url, src_url));
+  }
+
+  if (!copy) {
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnRemoveFile, MakeTuple(src_url));
     TouchDirectory(db, src_file_info.parent_id);
+  }
+
   TouchDirectory(db, dest_file_info.parent_id);
 
   UpdateUsage(context, dest_url, growth);
@@ -769,6 +795,14 @@ PlatformFileError ObfuscatedFileUtil::CopyInForeignFile(
   if (error != base::PLATFORM_FILE_OK)
     return error;
 
+  if (overwrite) {
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnModifyFile, MakeTuple(dest_url));
+  } else {
+    context->change_observers()->Notify(
+        &FileChangeObserver::OnCreateFile, MakeTuple(dest_url));
+  }
+
   UpdateUsage(context, dest_url, growth);
   TouchDirectory(db, dest_file_info.parent_id);
   return base::PLATFORM_FILE_OK;
@@ -809,6 +843,9 @@ PlatformFileError ObfuscatedFileUtil::DeleteFile(
   UpdateUsage(context, url, growth);
   TouchDirectory(db, file_info.parent_id);
 
+  context->change_observers()->Notify(
+      &FileChangeObserver::OnRemoveFile, MakeTuple(url));
+
   if (error == base::PLATFORM_FILE_ERROR_NOT_FOUND)
     return base::PLATFORM_FILE_OK;
 
@@ -840,6 +877,8 @@ PlatformFileError ObfuscatedFileUtil::DeleteSingleDirectory(
   AllocateQuota(context, growth);
   UpdateUsage(context, url, growth);
   TouchDirectory(db, file_info.parent_id);
+  context->change_observers()->Notify(
+      &FileChangeObserver::OnRemoveDirectory, MakeTuple(url));
   return base::PLATFORM_FILE_OK;
 }
 
diff --git a/webkit/fileapi/obfuscated_file_util_unittest.cc b/webkit/fileapi/obfuscated_file_util_unittest.cc
index 76c28ba..a7f9c4b 100644
--- a/webkit/fileapi/obfuscated_file_util_unittest.cc
+++ b/webkit/fileapi/obfuscated_file_util_unittest.cc
@@ -21,6 +21,7 @@
 #include "webkit/fileapi/file_system_usage_cache.h"
 #include "webkit/fileapi/file_util_helper.h"
 #include "webkit/fileapi/local_file_system_test_helper.h"
+#include "webkit/fileapi/mock_file_change_observer.h"
 #include "webkit/fileapi/mock_file_system_options.h"
 #include "webkit/fileapi/obfuscated_file_util.h"
 #include "webkit/fileapi/test_file_set.h"
@@ -28,7 +29,7 @@
 #include "webkit/quota/quota_manager.h"
 #include "webkit/quota/quota_types.h"
 
-using namespace fileapi;
+namespace fileapi {
 
 namespace {
 
@@ -133,6 +134,8 @@ class ObfuscatedFileUtilTest : public testing::Test {
 
     test_helper_.SetUp(file_system_context_.get(),
                        obfuscated_file_util_);
+
+    change_observers_ = MockFileChangeObserver::CreateList(&change_observer_);
   }
 
   void TearDown() {
@@ -154,15 +157,25 @@ class ObfuscatedFileUtilTest : public testing::Test {
 
   FileSystemOperationContext* NewContext(
       LocalFileSystemTestOriginHelper* helper) {
+    change_observer()->ResetCount();
     FileSystemOperationContext* context;
     if (helper)
       context = helper->NewOperationContext();
     else
       context = test_helper_.NewOperationContext();
     context->set_allowed_bytes_growth(1024 * 1024); // Big enough for all tests.
+    context->set_change_observers(change_observers());
     return context;
   }
 
+  const ChangeObserverList& change_observers() const {
+    return change_observers_;
+  }
+
+  MockFileChangeObserver* change_observer() {
+    return &change_observer_;
+  }
+
   // This can only be used after SetUp has run and created file_system_context_
   // and obfuscated_file_util_.
   // Use this for tests which need to run in multiple origins; we need a test
@@ -428,6 +441,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
                   context.get(), ofu(), root_url, &entries));
     std::vector<base::FileUtilProxy::Entry>::iterator entry_iter;
     EXPECT_EQ(files.size() + directories.size(), entries.size());
+    EXPECT_TRUE(change_observer()->HasNoChange());
     for (entry_iter = entries.begin(); entry_iter != entries.end();
         ++entry_iter) {
       const base::FileUtilProxy::Entry& entry = *entry_iter;
@@ -452,6 +466,8 @@ class ObfuscatedFileUtilTest : public testing::Test {
     EXPECT_EQ(base::PLATFORM_FILE_OK,
               ofu()->Touch(
                   context.get(), url, last_access_time, last_modified_time));
+    // Currently we fire no change notifications for Touch.
+    EXPECT_TRUE(change_observer()->HasNoChange());
     FilePath local_path;
     base::PlatformFileInfo file_info;
     context.reset(NewContext(NULL));
@@ -468,6 +484,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
     EXPECT_EQ(base::PLATFORM_FILE_OK,
               ofu()->Touch(
                   context.get(), url, last_access_time, last_modified_time));
+    EXPECT_TRUE(change_observer()->HasNoChange());
     context.reset(NewContext(NULL));
     EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->GetFileInfo(
         context.get(), url, &file_info, &local_path));
@@ -503,6 +520,10 @@ class ObfuscatedFileUtilTest : public testing::Test {
       EXPECT_EQ(base::PLATFORM_FILE_OK,
           ofu()->EnsureFileExists(context.get(), dest_url, &created));
       EXPECT_TRUE(created);
+
+      // We must have observed one (and only one) create_file_count.
+      EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
+      EXPECT_TRUE(change_observer()->HasNoChange());
     }
 
     const int64 path_cost =
@@ -552,6 +573,7 @@ class ObfuscatedFileUtilTest : public testing::Test {
     context.reset(NewContext(NULL));
     EXPECT_EQ(base::PLATFORM_FILE_OK,
               ofu()->GetFileInfo(context.get(), url, &file_info, &data_path));
+    EXPECT_TRUE(change_observer()->HasNoChange());
     return file_info.last_modified;
   }
 
@@ -594,7 +616,6 @@ class ObfuscatedFileUtilTest : public testing::Test {
               ofu()->CopyOrMoveFile(context.get(),
                                     src_file_url, dest_file_url,
                                     copy));
-
     if (copy)
       EXPECT_EQ(base::Time(), GetModifiedTime(src_dir_url));
     else
@@ -623,6 +644,8 @@ class ObfuscatedFileUtilTest : public testing::Test {
   LocalFileSystemTestOriginHelper test_helper_;
   quota::QuotaStatusCode quota_status_;
   int64 usage_;
+  MockFileChangeObserver change_observer_;
+  ChangeObserverList change_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ObfuscatedFileUtilTest);
 };
@@ -645,6 +668,8 @@ TEST_F(ObfuscatedFileUtilTest, TestCreateAndDeleteFile) {
 
   url = CreateURLFromUTF8("test file");
 
+  EXPECT_TRUE(change_observer()->HasNoChange());
+
   // Verify that file creation requires sufficient quota for the path.
   context.reset(NewContext(NULL));
   context->set_allowed_bytes_growth(
@@ -660,6 +685,7 @@ TEST_F(ObfuscatedFileUtilTest, TestCreateAndDeleteFile) {
             ofu()->CreateOrOpen(
                 context.get(), url, file_flags, &file_handle, &created));
   ASSERT_TRUE(created);
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
   EXPECT_NE(base::kInvalidPlatformFileValue, file_handle);
 
   CheckFileAndCloseHandle(url, file_handle);
@@ -676,6 +702,7 @@ TEST_F(ObfuscatedFileUtilTest, TestCreateAndDeleteFile) {
   context->set_allowed_bytes_growth(0);
   EXPECT_EQ(base::PLATFORM_FILE_OK,
             ofu()->DeleteFile(context.get(), url));
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_file_count());
   EXPECT_FALSE(file_util::PathExists(local_path));
   EXPECT_EQ(ObfuscatedFileUtil::ComputeFilePathCost(url.path()),
       context->allowed_bytes_growth());
@@ -688,6 +715,8 @@ TEST_F(ObfuscatedFileUtilTest, TestCreateAndDeleteFile) {
   url = directory_url.WithPath(directory_url.path().AppendASCII("file name"));
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->CreateDirectory(
       context.get(), directory_url, exclusive, recursive));
+  // The oepration created 3 directories recursively.
+  EXPECT_EQ(3, change_observer()->get_and_reset_create_directory_count());
 
   context.reset(NewContext(NULL));
   file_handle = base::kInvalidPlatformFileValue;
@@ -695,6 +724,7 @@ TEST_F(ObfuscatedFileUtilTest, TestCreateAndDeleteFile) {
             ofu()->CreateOrOpen(
                 context.get(), url, file_flags, &file_handle, &created));
   ASSERT_TRUE(created);
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
   EXPECT_NE(base::kInvalidPlatformFileValue, file_handle);
 
   CheckFileAndCloseHandle(url, file_handle);
@@ -707,7 +737,11 @@ TEST_F(ObfuscatedFileUtilTest, TestCreateAndDeleteFile) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_OK,
             ofu()->DeleteFile(context.get(), url));
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_file_count());
   EXPECT_FALSE(file_util::PathExists(local_path));
+
+  // Make sure we have no unexpected changes.
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestTruncate) {
@@ -722,6 +756,7 @@ TEST_F(ObfuscatedFileUtilTest, TestTruncate) {
   ASSERT_EQ(base::PLATFORM_FILE_OK,
       ofu()->EnsureFileExists(context.get(), url, &created));
   ASSERT_TRUE(created);
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
 
   context.reset(NewContext(NULL));
   FilePath local_path;
@@ -732,15 +767,20 @@ TEST_F(ObfuscatedFileUtilTest, TestTruncate) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->Truncate(
       context.get(), url, 10));
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
   EXPECT_EQ(10, GetSize(local_path));
 
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->Truncate(
       context.get(), url, 1));
   EXPECT_EQ(1, GetSize(local_path));
+  EXPECT_EQ(1, change_observer()->get_and_reset_modify_file_count());
 
   EXPECT_FALSE(DirectoryExists(url));
   EXPECT_TRUE(PathExists(url));
+
+  // Make sure we have no unexpected changes.
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestQuotaOnTruncation) {
@@ -817,6 +857,7 @@ TEST_F(ObfuscatedFileUtilTest, TestEnsureFileExists) {
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND,
             ofu()->EnsureFileExists(
                 context.get(), url, &created));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   // Verify that file creation requires sufficient quota for the path.
   context.reset(NewContext(NULL));
@@ -827,6 +868,7 @@ TEST_F(ObfuscatedFileUtilTest, TestEnsureFileExists) {
   ASSERT_EQ(base::PLATFORM_FILE_ERROR_NO_SPACE,
             ofu()->EnsureFileExists(context.get(), url, &created));
   ASSERT_FALSE(created);
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   context.reset(NewContext(NULL));
   context->set_allowed_bytes_growth(
@@ -834,6 +876,7 @@ TEST_F(ObfuscatedFileUtilTest, TestEnsureFileExists) {
   ASSERT_EQ(base::PLATFORM_FILE_OK,
             ofu()->EnsureFileExists(context.get(), url, &created));
   ASSERT_TRUE(created);
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_file_count());
 
   CheckFileAndCloseHandle(url, base::kInvalidPlatformFileValue);
 
@@ -841,6 +884,7 @@ TEST_F(ObfuscatedFileUtilTest, TestEnsureFileExists) {
   ASSERT_EQ(base::PLATFORM_FILE_OK,
             ofu()->EnsureFileExists(context.get(), url, &created));
   ASSERT_FALSE(created);
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   // Also test in a subdirectory.
   url = CreateURLFromUTF8("path/to/file.txt");
@@ -851,6 +895,8 @@ TEST_F(ObfuscatedFileUtilTest, TestEnsureFileExists) {
       context.get(),
       url.WithPath(url.path().DirName()),
       exclusive, recursive));
+  // 2 directories: path/ and path/to.
+  EXPECT_EQ(2, change_observer()->get_and_reset_create_directory_count());
 
   context.reset(NewContext(NULL));
   ASSERT_EQ(base::PLATFORM_FILE_OK,
@@ -858,6 +904,7 @@ TEST_F(ObfuscatedFileUtilTest, TestEnsureFileExists) {
   ASSERT_TRUE(created);
   EXPECT_FALSE(DirectoryExists(url));
   EXPECT_TRUE(PathExists(url));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
@@ -884,6 +931,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   recursive = true;
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_EQ(2, change_observer()->get_and_reset_create_directory_count());
 
   EXPECT_TRUE(DirectoryExists(url));
   EXPECT_TRUE(PathExists(url));
@@ -901,6 +949,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_EMPTY,
       ofu()->DeleteSingleDirectory(context.get(),
                                    url.WithPath(url.path().DirName())));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   base::PlatformFileInfo file_info;
   FilePath local_path;
@@ -914,12 +963,14 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   exclusive = true;
   recursive = true;
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   // Verify that deleting a directory isn't stopped by zero quota, and that it
   // frees up quota from its path.
@@ -927,6 +978,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   context->set_allowed_bytes_growth(0);
   EXPECT_EQ(base::PLATFORM_FILE_OK,
       ofu()->DeleteSingleDirectory(context.get(), url));
+  EXPECT_EQ(1, change_observer()->get_and_reset_remove_directory_count());
   EXPECT_EQ(ObfuscatedFileUtil::ComputeFilePathCost(url.path()),
       context->allowed_bytes_growth());
 
@@ -948,12 +1000,14 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
       ObfuscatedFileUtil::ComputeFilePathCost(url.path()) - 1);
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NO_SPACE, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   context.reset(NewContext(NULL));
   context->set_allowed_bytes_growth(
       ObfuscatedFileUtil::ComputeFilePathCost(url.path()));
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
 
   EXPECT_TRUE(DirectoryExists(url));
   EXPECT_TRUE(PathExists(url));
@@ -963,6 +1017,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   exclusive = true;
   recursive = false;
@@ -970,6 +1025,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 
   url = CreateURLFromUTF8("blah");
 
@@ -981,6 +1037,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_EQ(1, change_observer()->get_and_reset_create_directory_count());
 
   EXPECT_TRUE(DirectoryExists(url));
   EXPECT_TRUE(PathExists(url));
@@ -990,6 +1047,7 @@ TEST_F(ObfuscatedFileUtilTest, TestDirectoryOps) {
   context.reset(NewContext(NULL));
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_EXISTS, ofu()->CreateDirectory(
       context.get(), url, exclusive, recursive));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestReadDirectory) {
@@ -1103,11 +1161,13 @@ TEST_F(ObfuscatedFileUtilTest, TestCopyOrMoveFileNotFound) {
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND,
       ofu()->CopyOrMoveFile(context.get(), source_url, dest_url,
           is_copy_not_move));
+  EXPECT_TRUE(change_observer()->HasNoChange());
   context.reset(NewContext(NULL));
   is_copy_not_move = true;
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND,
       ofu()->CopyOrMoveFile(context.get(), source_url, dest_url,
           is_copy_not_move));
+  EXPECT_TRUE(change_observer()->HasNoChange());
   source_url = CreateURLFromUTF8("dir/dir/file");
   bool exclusive = true;
   bool recursive = true;
@@ -1116,15 +1176,18 @@ TEST_F(ObfuscatedFileUtilTest, TestCopyOrMoveFileNotFound) {
       context.get(),
       source_url.WithPath(source_url.path().DirName()),
       exclusive, recursive));
+  EXPECT_EQ(2, change_observer()->get_and_reset_create_directory_count());
   is_copy_not_move = false;
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND,
       ofu()->CopyOrMoveFile(context.get(), source_url, dest_url,
           is_copy_not_move));
+  EXPECT_TRUE(change_observer()->HasNoChange());
   context.reset(NewContext(NULL));
   is_copy_not_move = true;
   EXPECT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND,
       ofu()->CopyOrMoveFile(context.get(), source_url, dest_url,
           is_copy_not_move));
+  EXPECT_TRUE(change_observer()->HasNoChange());
 }
 
 TEST_F(ObfuscatedFileUtilTest, TestCopyOrMoveFileSuccess) {
@@ -1183,6 +1246,7 @@ TEST_F(ObfuscatedFileUtilTest, TestCopyOrMoveFileSuccess) {
     context.reset(NewContext(NULL));
     EXPECT_EQ(base::PLATFORM_FILE_OK, ofu()->CopyOrMoveFile(context.get(),
         source_url, dest_url, test_case.is_copy_not_move));
+
     if (test_case.is_copy_not_move) {
       base::PlatformFileInfo file_info;
       FilePath local_path;
@@ -2210,3 +2274,5 @@ TEST_F(ObfuscatedFileUtilTest, TestQuotaOnOpen) {
   ASSERT_EQ(0, ComputeTotalFileSize());
   EXPECT_TRUE(base::ClosePlatformFile(file_handle));
 }
+
+}  // namespace fileapi
diff --git a/webkit/fileapi/task_runner_bound_observer_list.h b/webkit/fileapi/task_runner_bound_observer_list.h
index 17a8eec..9af380f5c 100644
--- a/webkit/fileapi/task_runner_bound_observer_list.h
+++ b/webkit/fileapi/task_runner_bound_observer_list.h
@@ -94,9 +94,11 @@ class TaskRunnerBoundObserverList {
 };
 
 class FileAccessObserver;
+class FileChangeObserver;
 class FileUpdateObserver;
 
 typedef TaskRunnerBoundObserverList<FileAccessObserver> AccessObserverList;
+typedef TaskRunnerBoundObserverList<FileChangeObserver> ChangeObserverList;
 typedef TaskRunnerBoundObserverList<FileUpdateObserver> UpdateObserverList;
 
 }  // namespace fileapi