gdata: Support mounting archive files in GData cache.

chrome/browser/chromeos/gdata/gdata_util.h

Index: chrome/browser/chromeos/gdata/gdata_util.h
diff --git a/chrome/browser/chromeos/gdata/gdata_util.h b/chrome/browser/chromeos/gdata/gdata_util.h
index a7f5cd86ebc68d9ae30d359f96764de67a8f10cd..f1ff2efe90382a635861c2ea169c5ff27f9466a4 100644
--- a/chrome/browser/chromeos/gdata/gdata_util.h
+++ b/chrome/browser/chromeos/gdata/gdata_util.h
@@ -62,6 +62,21 @@ void SetPermissionsForGDataCacheFiles(Profile* profile,
 
 // Returns true if gdata is currently active with the specified profile.
 bool IsGDataAvailable(Profile* profile);
+
+// Extracts resource_id, md5, and extra_extension from cache path.
+// Case 1: Pinned and outgoing symlinks only have resource_id.
+// Example: path="/user/GCache/v1/pinned/pdf:a1b2" =>
+//          resource_id="pdf:a1b2", md5="", extra_extension="";
+// Case 2: Normal files have both resource_id and md5.
+// Example: path="/user/GCache/v1/tmp/pdf:a1b2.01234567" =>
+//          resource_id="pdf:a1b2", md5="01234567", extra_extension="";
+// Case 3: Mounted files have all three parts.
+// Example: path="/user/GCache/v1/persistent/pdf:a1b2.01234567.mounted" =>
+//          resource_id="pdf:a1b2", md5="01234567", extra_extension="mounted".
+void ParseCacheFilePath(const FilePath& path,
+                        std::string* resource_id,
+                        std::string* md5,
+                        std::string* extra_extension);
 }  // namespace util
 }  // namespace gdata