mediaview: Implement ArcDocumentsProviderRoot.

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h

Index: chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h
diff --git a/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h b/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h
index 41135c9e0c255c8eef3c49e1278c1ad11362bc45..123b268ed337951687eeabdd95f707f058a860ea 100644
--- a/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h
+++ b/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.h
@@ -5,17 +5,26 @@
 #ifndef CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_ROOT_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_ROOT_H_
 
+#include <memory>
 #include <string>
+#include <vector>
 
 #include "base/files/file_path.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/optional.h"
+#include "components/arc/common/file_system.mojom.h"
 #include "storage/browser/fileapi/async_file_util.h"
 
 namespace arc {
 
+class ArcDocumentsProviderDocument;
+
 // Represents a file system root in Android Documents Provider.
 //
 // All methods must be called on the IO thread.
+// If this object is deleted while there are in-flight operations, callbacks
+// for those operations will be never called.
 class ArcDocumentsProviderRoot {
  public:
   using GetFileInfoCallback = storage::AsyncFileUtil::GetFileInfoCallback;
@@ -35,6 +44,33 @@ class ArcDocumentsProviderRoot {
                      const ReadDirectoryCallback& callback);
 
  private:
+  void GetFileInfoAfterCacheUpdate(const base::FilePath& path,
+                                   const GetFileInfoCallback& callback);
+  void GetFileInfoWithDocument(const GetFileInfoCallback& callback,
+                               mojom::DocumentPtr document);
+
+  void ReadDirectoryAfterCacheUpdate(const base::FilePath& path,
+                                     const ReadDirectoryCallback& callback);
+  void ReadDirectoryWithChildDocuments(
+      const base::FilePath& path,
+      const ReadDirectoryCallback& callback,
+      base::Optional<std::vector<mojom::DocumentPtr>> children);
+
+  void UpdateDirectoryCacheUpTo(const base::FilePath& path,

[hashimoto, 2016/12/19 06:40:48]

Please add a comment to describe what this method does.
What does "cache" mean?
What does "up to" mean?

[Shuhei Takahashi, 2016/12/19 10:01:56]

N/A

+                                const base::Closure& callback);
+  void UpdateDirectoryCacheIter(const base::FilePath& parent_directory_path,

[hashimoto, 2016/12/19 06:40:48]

What does "iter" mean?
Generally speaking, you should avoid abbreviation
https://google.github.io/styleguide/cppguide.html#General_Naming_Rules

[Shuhei Takahashi, 2016/12/19 10:01:56]

N/A

+                                const base::FilePath& remaining_path,
+                                const base::Closure& callback);
+  void UpdateDirectoryCacheIterWithChildDocuments(
+      const base::FilePath& parent_directory_path,
+      const base::FilePath& remaining_path,
+      const base::Closure& callback,
+      base::Optional<std::vector<mojom::DocumentPtr>> children);
+
+  const std::string authority_;
+  const std::unique_ptr<ArcDocumentsProviderDocument> root_directory_;
+  base::WeakPtrFactory<ArcDocumentsProviderRoot> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ArcDocumentsProviderRoot);
 };