A bunch of remaining parts of extension content verification (Reland)

extensions/common/constants.h

Index: extensions/common/constants.h
diff --git a/extensions/common/constants.h b/extensions/common/constants.h
index 20bf421cd65428e77819ecf6dd3f189c070afde1..66fe2ba4d1e6b9250a5bcc29a3940945fa914c50 100644
--- a/extensions/common/constants.h
+++ b/extensions/common/constants.h
@@ -28,6 +28,16 @@ extern const base::FilePath::CharType kMessagesFilename[];
 // The base directory for subdirectories with platform-specific code.
 extern const base::FilePath::CharType kPlatformSpecificFolder[];
 
+// A directory reserved for metadata, generated either by the webstore
+// or chrome.
+extern const base::FilePath::CharType kMetadataFolder[];
+
+// Name of the verified contents file within the metadata folder.
+extern const base::FilePath::CharType kVerifiedContentsFilename[];
+
+// Name of the computed hashes file within the metadata folder.
+extern const base::FilePath::CharType kComputedHashesFilename[];
+
 // The name of the directory inside the profile where extensions are
 // installed to.
 extern const char kInstallDirectoryName[];