[SafeBrowsing] Consolidate extension lookup logic and extension lists.

chrome/common/safe_browsing/download_protection_util.h

Index: chrome/common/safe_browsing/download_protection_util.h
diff --git a/chrome/common/safe_browsing/download_protection_util.h b/chrome/common/safe_browsing/download_protection_util.h
index 248a343222fac44f79db87cba0db3530d6d05efc..9fc0e3be0697040a0642fbee79019ca719ffcf2f 100644
--- a/chrome/common/safe_browsing/download_protection_util.h
+++ b/chrome/common/safe_browsing/download_protection_util.h
@@ -24,6 +24,12 @@ bool IsArchiveFile(const base::FilePath& file);
 // for paths that satisfy IsSupportedBinaryFile() above.
 ClientDownloadRequest::DownloadType GetDownloadType(const base::FilePath& file);
 
+// The maximum value returned by GetSBClientDownloadExtensionValueForUMA() + 1.
+extern const int kSBClientDownloadExtensionsMax;
+
+// SBClientDownloadExtensions UMA enum value corresponding to |file|.
+int GetSBClientDownloadExtensionValueForUMA(const base::FilePath& file);
+
 }  // namespace download_protection_util
 }  // namespace safe_browsing