Add a function for usage tracking. It's based on the bug 6426001.

BUG=
TEST=

Review URL: http://codereview.chromium.org/6453001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@76578 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 19 insertions, 1 deletions

diff --git a/webkit/fileapi/file_system_usage_tracker.cc b/webkit/fileapi/file_system_usage_tracker.cc
index f58e4aa..9456f2a 100644
--- a/webkit/fileapi/file_system_usage_tracker.cc
+++ b/webkit/fileapi/file_system_usage_tracker.cc
@@ -14,6 +14,7 @@
 #include "base/task.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/fileapi/file_system_path_manager.h"
+#include "webkit/fileapi/file_system_usage_cache.h"
 
 namespace fileapi {
 
@@ -52,7 +53,24 @@ class FileSystemUsageTracker::GetUsageTask
   void RunOnFileThread() {
     DCHECK(file_message_loop_->BelongsToCurrentThread());
 
-    // TODO(dmikurube): add the code that retrieves the origin usage here.
+    if (!file_util::DirectoryExists(origin_base_path_))
+      fs_usage_ = 0;
+    else {
+      FilePath usage_file_path = origin_base_path_.AppendASCII(
+          FileSystemUsageCache::kUsageFileName);
+      fs_usage_ = FileSystemUsageCache::GetUsage(usage_file_path);
+
+      if (fs_usage_ < 0) {
+        FilePath content_file_path = origin_base_path_;
+        if (FileSystemUsageCache::Exists(usage_file_path))
+          FileSystemUsageCache::Delete(usage_file_path);
+        fs_usage_ = file_util::ComputeDirectorySize(content_file_path);
+        // fs_usage_ will include the size of .usage.
+        // The result of ComputeDirectorySize does not include it.
+        fs_usage_ += FileSystemUsageCache::kUsageFileSize;
+        FileSystemUsageCache::UpdateUsage(usage_file_path, fs_usage_);
+      }
+    }
 
     original_message_loop_->PostTask(
         FROM_HERE, NewRunnableMethod(this, &GetUsageTask::Completed));