Extracting and unittesting PrepareDropDataForChildProcess function.

content/browser/fileapi/browser_file_system_helper.cc

Index: content/browser/fileapi/browser_file_system_helper.cc
diff --git a/content/browser/fileapi/browser_file_system_helper.cc b/content/browser/fileapi/browser_file_system_helper.cc
index d51abece3bd5d9580380b34587998bdd738263f5..c74b516ae40148f82fc78ffbd7f5f1776f320f8e 100644
--- a/content/browser/fileapi/browser_file_system_helper.cc
+++ b/content/browser/fileapi/browser_file_system_helper.cc
@@ -12,20 +12,28 @@
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/sequenced_task_runner.h"
+#include "base/strings/utf_string_conversions.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
+#include "content/public/common/drop_data.h"
+#include "content/public/common/url_constants.h"
+#include "net/base/filename_util.h"
 #include "storage/browser/fileapi/external_mount_points.h"
 #include "storage/browser/fileapi/file_permission_policy.h"
 #include "storage/browser/fileapi/file_system_backend.h"
 #include "storage/browser/fileapi/file_system_context.h"
 #include "storage/browser/fileapi/file_system_operation_runner.h"
 #include "storage/browser/fileapi/file_system_options.h"
+#include "storage/browser/fileapi/file_system_url.h"
+#include "storage/browser/fileapi/isolated_context.h"
 #include "storage/browser/quota/quota_manager.h"
+#include "url/gurl.h"
 #include "url/url_constants.h"
 
 namespace content {
@@ -132,4 +140,84 @@ void SyncGetPlatformPath(storage::FileSystemContext* context,
     policy->GrantReadFile(process_id, *platform_path);
 }
 
+void PrepareDropDataForChildProcess(
+    DropData* drop_data,
+    ChildProcessSecurityPolicyImpl* security_policy,
+    int child_id,
+    const storage::FileSystemContext* file_system_context) {
+#if defined(OS_CHROMEOS)
+  // The externalfile:// scheme is used in Chrome OS to open external files in a
+  // browser tab.
+  if (drop_data->url.SchemeIs(content::kExternalFileScheme))
+    security_policy->GrantRequestURL(child_id, drop_data->url);
+#endif
+
+  // The filenames vector represents a capability to access the given files.
+  storage::IsolatedContext::FileInfoSet files;
+  for (auto& filename : drop_data->filenames) {
+    // Make sure we have the same display_name as the one we register.
+    if (filename.display_name.empty()) {
+      std::string name;
+      files.AddPath(filename.path, &name);
+      filename.display_name = base::FilePath::FromUTF8Unsafe(name);
+    } else {
+      files.AddPathWithName(filename.path,
+                            filename.display_name.AsUTF8Unsafe());
+    }
+    // A dragged file may wind up as the value of an input element, or it
+    // may be used as the target of a navigation instead.  We don't know
+    // which will happen at this point, so generously grant both access
+    // and request permissions to the specific file to cover both cases.
+    // We do not give it the permission to request all file:// URLs.
+    security_policy->GrantRequestSpecificFileURL(
+        child_id, net::FilePathToFileURL(filename.path));
+
+    // If the renderer already has permission to read these paths, we don't need
+    // to re-grant them. This prevents problems with DnD for files in the CrOS
+    // file manager--the file manager already had read/write access to those
+    // directories, but dragging a file would cause the read/write access to be
+    // overwritten with read-only access, making them impossible to delete or
+    // rename until the renderer was killed.
+    if (!security_policy->CanReadFile(child_id, filename.path))
+      security_policy->GrantReadFile(child_id, filename.path);
+  }
+
+  storage::IsolatedContext* isolated_context =
+      storage::IsolatedContext::GetInstance();
+  DCHECK(isolated_context);
+
+  if (!files.fileset().empty()) {
+    std::string filesystem_id =
+        isolated_context->RegisterDraggedFileSystem(files);
+    if (!filesystem_id.empty()) {
+      // Grant the permission iff the ID is valid.
+      security_policy->GrantReadFileSystem(child_id, filesystem_id);
+    }
+    drop_data->filesystem_id = base::UTF8ToUTF16(filesystem_id);
+  }
+
+  for (auto& file_system_file : drop_data->file_system_files) {
+    storage::FileSystemURL file_system_url =
+        file_system_context->CrackURL(file_system_file.url);
+
+    std::string register_name;
+    std::string filesystem_id = isolated_context->RegisterFileSystemForPath(
+        file_system_url.type(), file_system_url.filesystem_id(),
+        file_system_url.path(), &register_name);
+
+    if (!filesystem_id.empty()) {
+      // Grant the permission iff the ID is valid.
+      security_policy->GrantReadFileSystem(child_id, filesystem_id);
+    }
+
+    // Note: We are using the origin URL provided by the sender here. It may be
+    // different from the receiver's.
+    file_system_file.url =
+        GURL(storage::GetIsolatedFileSystemRootURIString(
+                 file_system_url.origin(), filesystem_id, std::string())
+                 .append(register_name));
+    file_system_file.filesystem_id = filesystem_id;
+  }
+}
+
 }  // namespace content