Move TranslateManager unit tests out of the browser_tests target.

components/translate/core/browser/translate_download_manager.h

Index: components/translate/core/browser/translate_download_manager.h
diff --git a/components/translate/core/browser/translate_download_manager.h b/components/translate/core/browser/translate_download_manager.h
index 4766b652e575bf617c56f4828db55d8e2efc8e5e..ed8e04b1c42d74b7fba3d22c645df0429b7babc9 100644
--- a/components/translate/core/browser/translate_download_manager.h
+++ b/components/translate/core/browser/translate_download_manager.h
@@ -78,6 +78,9 @@ class TranslateDownloadManager {
   // Clears the translate script, so it will be fetched next time we translate.
   void ClearTranslateScriptForTesting();
 
+  // Resets to its initial state as if newly created.
+  void ResetForTesting();
+
   // Used by unit-tests to override some defaults:
   // Delay after which the translate script is fetched again from the
   // translation server.