Fix filesystem API file_handlers to work for drive on ChromeOS.

webkit/fileapi/file_system_context.cc

Index: webkit/fileapi/file_system_context.cc
diff --git a/webkit/fileapi/file_system_context.cc b/webkit/fileapi/file_system_context.cc
index 017cf29f417ed78b3a73a84a6a864fdbf0f909b5..762f24cae9b000040f13ecb399721c795fc875a8 100644
--- a/webkit/fileapi/file_system_context.cc
+++ b/webkit/fileapi/file_system_context.cc
@@ -359,14 +359,58 @@ FileSystemURL FileSystemContext::CrackFileSystemURL(
                                                           url.type(),
                                                           url.path());
     if (result.is_valid())
-      return result;
+      break;
   }
 
+  FileSystemType underlying_mount_type = GetUnderlyingMountType(result);
+  if (underlying_mount_type != fileapi::kFileSystemTypeUnknown) {
+    base::FilePath underlying_virtual_path;
+    if (GetVirtualPath(underlying_mount_type, result.path(),
+                       &underlying_virtual_path)) {
+      // Note the recursion.
+      FileSystemURL underlying_url =
+          CreateCrackedFileSystemURL(result.origin(),
+                                     underlying_mount_type,
+                                     underlying_virtual_path);
+      if (underlying_url.is_valid()) {
+        result.SetUnderlyingURL(underlying_url);
+      }
+    }
+  }
   return result;
 }
 
+FileSystemType FileSystemContext::GetUnderlyingMountType(
+    const FileSystemURL& url) const {
+  if (external_provider() &&
+      url.is_valid() &&
+      url.type() == fileapi::kFileSystemTypeNativeLocal &&
+      url.mount_type() == fileapi::kFileSystemTypeIsolated) {
+    return kFileSystemTypeExternal;
+  }
+  return kFileSystemTypeUnknown;
+
+}
+
+bool FileSystemContext::GetVirtualPath(
+    FileSystemType mount_type,
+    const base::FilePath& full_path,
+    base::FilePath* virtual_path) const {
+  DCHECK(virtual_path);
+
+  for (size_t i = 0; i < url_crackers_.size(); ++i) {
+    if (!url_crackers_[i]->HandlesFileSystemMountType(mount_type))
+      continue;
+
+    if (url_crackers_[i]->GetVirtualPath(full_path, virtual_path))
+      return true;
+  }
+
+  return false;
+}
+
 FileSystemFileUtil* FileSystemContext::GetFileUtil(
-    FileSystemType type) const {
+    fileapi::FileSystemType type) const {
   FileSystemMountPointProvider* mount_point_provider =
       GetMountPointProvider(type);
   if (!mount_point_provider)