Collect some histograms about signed binary downloads.

chrome/browser/safe_browsing/download_protection_service.h

Index: chrome/browser/safe_browsing/download_protection_service.h
===================================================================
--- chrome/browser/safe_browsing/download_protection_service.h	(revision 106177)
+++ chrome/browser/safe_browsing/download_protection_service.h	(working copy)
@@ -18,6 +18,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/time.h"
 #include "content/common/net/url_fetcher.h"
 #include "googleurl/src/gurl.h"
@@ -36,9 +37,10 @@
     : public base::RefCountedThreadSafe<DownloadProtectionService>,
       public URLFetcher::Delegate {
  public:
-  // TODO(noelutz): we're missing some fields here: filename to get
-  // the signature, server IPs, tab URL redirect chain, ...
+  // TODO(noelutz): we're missing some fields here: server IPs,
+  // tab URL redirect chain, ...
   struct DownloadInfo {
+    FilePath local_file;
     std::vector<GURL> download_url_chain;
     GURL referrer_url;
     std::string sha256_hash;
@@ -62,7 +64,7 @@
   // to call SetEnabled() to start it.  We keep scoped references to both of
   // these objects.
   DownloadProtectionService(
-      SafeBrowsingService* sb_service,
+      const base::WeakPtr<SafeBrowsingService>& sb_service,
       net::URLRequestContextGetter* request_context_getter);
 
   // From the URLFetcher::Delegate interface.
@@ -107,6 +109,7 @@
     REASON_INVALID_REQUEST_PROTO,
     REASON_SERVER_PING_FAILED,
     REASON_INVALID_RESPONSE_PROTO,
+    REASON_NOT_BINARY_FILE,
     REASON_MAX  // Always add new values before this one.
   };
 
@@ -124,6 +127,11 @@
 
   static const char kDownloadRequestUrl[];
 
+  // Extracts features from the downloaded file.  Runs in the file thread.
+  // When finished, invokes StartCheckClientDownload on the IO thread.
+  void ExtractFileFeatures(const DownloadInfo& info,
+                           const CheckDownloadCallback& callback);
+
   // Same as above but this method is called on the IO thread after we have
   // done some basic checks to see whether the download is definitely not
   // safe.
@@ -142,7 +150,7 @@
   void SetEnabledOnIOThread(bool enableed);
 
   // This pointer may be NULL if SafeBrowsing is disabled.
-  scoped_refptr<SafeBrowsingService> sb_service_;
+  base::WeakPtr<SafeBrowsingService> sb_service_;
 
   // The context we use to issue network requests.
   scoped_refptr<net::URLRequestContextGetter> request_context_getter_;