AU: Update Downloader to support our image formats.

src/platform/update_engine/test_utils.h

Index: src/platform/update_engine/test_utils.h
diff --git a/src/platform/update_engine/test_utils.h b/src/platform/update_engine/test_utils.h
index 4bc107e03e23ed41d50fdbb403e130e756a52281..ca797d96508c3870324d088207d7d91946a6cb58 100644
--- a/src/platform/update_engine/test_utils.h
+++ b/src/platform/update_engine/test_utils.h
@@ -9,8 +9,10 @@
 #include <string>
 #include <vector>
 #include <gtest/gtest.h>
+#include "base/scoped_ptr.h"
 #include "update_engine/action.h"
 #include "update_engine/subprocess.h"
+#include "update_engine/utils.h"
 
 // These are some handy functions for unittests.
 
@@ -119,6 +121,20 @@ class ScopedLoopbackDeviceReleaser {
   DISALLOW_COPY_AND_ASSIGN(ScopedLoopbackDeviceReleaser);
 };
 
+class ScopedTempFile {
+ public:
+  ScopedTempFile() {
+    EXPECT_TRUE(utils::MakeTempFile("/tmp/update_engine_test_temp_file.XXXXXX",
+                                    &path_,
+                                    NULL));
+    unlinker_.reset(new ScopedPathUnlinker(path_));
+  }
+  const std::string& GetPath() { return path_; }
+ private:
+  std::string path_;
+  scoped_ptr<ScopedPathUnlinker> unlinker_;
+};
+
 // Useful actions for test
 
 class NoneType;
@@ -191,4 +207,4 @@ struct ObjectCollectorAction : public Action<ObjectCollectorAction<T> > {
 
 }  // namespace chromeos_update_engine
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__