Add sampling of unknown filetypes in download protection.

chrome/browser/safe_browsing/download_protection_service.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Helper class which handles communication with the SafeBrowsing servers for
 // improved binary download protection.
 
 #ifndef CHROME_BROWSER_SAFE_BROWSING_DOWNLOAD_PROTECTION_SERVICE_H_
 #define CHROME_BROWSER_SAFE_BROWSING_DOWNLOAD_PROTECTION_SERVICE_H_
 
@@ skipping 89 matching lines @@
   // Checks whether any of the URLs in the redirect chain of the
   // download match the SafeBrowsing bad binary URL list.  The result is
   // delivered asynchronously via the given callback.  This method must be
   // called on the UI thread, and the callback will also be invoked on the UI
   // thread.  Pre-condition: !info.download_url_chain.empty().
   virtual void CheckDownloadUrl(const content::DownloadItem& item,
                                 const CheckDownloadCallback& callback);
 
   // Returns true iff the download specified by |info| should be scanned by
   // CheckClientDownload() for malicious content.
-  virtual bool IsSupportedDownload(const content::DownloadItem& item,
-                                   const base::FilePath& target_path) const;
+  virtual bool IsSupportedDownload(
+      const content::DownloadItem& item,
+      const base::FilePath& target_path) const;
 
   virtual void CheckPPAPIDownloadRequest(
       const GURL& requestor_url,
       const base::FilePath& default_file_path,
       const std::vector<base::FilePath::StringType>& alternate_extensions,
       const CheckDownloadCallback& callback);
 
   // Display more information to the user regarding the download specified by
   // |info|. This method is invoked when the user requests more information
   // about a download that was marked as malicious.
@@ skipping 28 matching lines @@
     return whitelist_sample_rate_;
   }
 
   static void SetDownloadPingToken(content::DownloadItem* item,
                                    const std::string& token);
 
   static std::string GetDownloadPingToken(const content::DownloadItem* item);
 
  protected:
   // Enum to keep track why a particular download verdict was chosen.
-  // This is used to keep some stats around.
+  // Used for UMA metrics. Do not reorder.
   enum DownloadCheckResultReason {
-    REASON_INVALID_URL,
-    REASON_SB_DISABLED,
-    REASON_WHITELISTED_URL,
-    REASON_WHITELISTED_REFERRER,
-    REASON_INVALID_REQUEST_PROTO,
-    REASON_SERVER_PING_FAILED,
-    REASON_INVALID_RESPONSE_PROTO,
-    REASON_NOT_BINARY_FILE,
-    REASON_REQUEST_CANCELED,
-    REASON_DOWNLOAD_DANGEROUS,
-    REASON_DOWNLOAD_SAFE,
-    REASON_EMPTY_URL_CHAIN,
-    DEPRECATED_REASON_HTTPS_URL,
-    REASON_PING_DISABLED,
-    REASON_TRUSTED_EXECUTABLE,
-    REASON_OS_NOT_SUPPORTED,
-    REASON_DOWNLOAD_UNCOMMON,
-    REASON_DOWNLOAD_NOT_SUPPORTED,
-    REASON_INVALID_RESPONSE_VERDICT,
-    REASON_ARCHIVE_WITHOUT_BINARIES,
-    REASON_DOWNLOAD_DANGEROUS_HOST,
-    REASON_DOWNLOAD_POTENTIALLY_UNWANTED,
-    REASON_UNSUPPORTED_URL_SCHEME,
-    REASON_MANUAL_BLACKLIST,
-    REASON_LOCAL_FILE,
-    REASON_REMOTE_FILE,
+    REASON_INVALID_URL = 0,
+    REASON_SB_DISABLED = 1,
+    REASON_WHITELISTED_URL = 2,
+    REASON_WHITELISTED_REFERRER = 3,
+    REASON_INVALID_REQUEST_PROTO = 4,
+    REASON_SERVER_PING_FAILED = 5,
+    REASON_INVALID_RESPONSE_PROTO = 6,
+    REASON_NOT_BINARY_FILE = 7,
+    REASON_REQUEST_CANCELED = 8,
+    REASON_DOWNLOAD_DANGEROUS = 9,
+    REASON_DOWNLOAD_SAFE = 10,
+    REASON_EMPTY_URL_CHAIN = 11,
+    DEPRECATED_REASON_HTTPS_URL = 12,
+    REASON_PING_DISABLED = 13,
+    REASON_TRUSTED_EXECUTABLE = 14,
+    REASON_OS_NOT_SUPPORTED = 15,
+    REASON_DOWNLOAD_UNCOMMON = 16,
+    REASON_DOWNLOAD_NOT_SUPPORTED = 17,
+    REASON_INVALID_RESPONSE_VERDICT = 18,
+    REASON_ARCHIVE_WITHOUT_BINARIES = 19,
+    REASON_DOWNLOAD_DANGEROUS_HOST = 20,
+    REASON_DOWNLOAD_POTENTIALLY_UNWANTED = 21,
+    REASON_UNSUPPORTED_URL_SCHEME = 22,
+    REASON_MANUAL_BLACKLIST = 23,
+    REASON_LOCAL_FILE = 24,
+    REASON_REMOTE_FILE = 25,
+    REASON_SAMPLED_UNSUPPORTED_FILE = 26,
     REASON_MAX  // Always add new values before this one.
   };
 
  private:
   class CheckClientDownloadRequest;
   class PPAPIDownloadRequest;
   friend class DownloadProtectionServiceTest;
   friend class DownloadDangerPromptTest;
 
   FRIEND_TEST_ALL_PREFIXES(DownloadProtectionServiceTest,
@@ skipping 100 matching lines @@
   std::set<std::string> manual_blacklist_hashes_;
 
   // Rate of whitelisted downloads we sample to send out download ping.
   double whitelist_sample_rate_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadProtectionService);
 };
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_DOWNLOAD_PROTECTION_SERVICE_H_