Send safe browsing ThreatDetails to track download CTR when user tries to recover blocked downloads

chrome/browser/download/download_danger_prompt.h

Index: chrome/browser/download/download_danger_prompt.h
diff --git a/chrome/browser/download/download_danger_prompt.h b/chrome/browser/download/download_danger_prompt.h
index e1b5c612c08994378a2e598440e948009d6aef82..84ef3f84d7ae69d8cc3e4d6990a3770c3ef7bcc3 100644
--- a/chrome/browser/download/download_danger_prompt.h
+++ b/chrome/browser/download/download_danger_prompt.h
@@ -5,7 +5,10 @@
 #ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_DANGER_PROMPT_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_DANGER_PROMPT_H_
 
+#include <string>
+
 #include "base/callback_forward.h"
+#include "url/gurl.h"
 
 namespace content {
 class DownloadItem;
@@ -37,15 +40,27 @@ class DownloadDangerPrompt {
   // caller does not own the object and receive no guarantees about lifetime.
   // If |show_context|, then the prompt message will contain some information
   // about the download and its danger; otherwise it won't.
-  static DownloadDangerPrompt* Create(
-      content::DownloadItem* item,
-      content::WebContents* web_contents,
-      bool show_context,
-      const OnDone& done);
-
-  // Only to be used by tests. Subclasses must override to manually call the
-  // respective button click handler.
-  virtual void InvokeActionForTesting(Action action) = 0;
+  static DownloadDangerPrompt* Create(content::DownloadItem* item,
+                                      content::WebContents* web_contents,
+                                      bool show_context,
+                                      const OnDone& done);
+
+  // Helper function only used by tests. This function returns a serialized
+  // ClientSafeBrowsingReportRequest proto or an empty string. Subclasses must
+  // override to manually call the respective button click handler.
+  virtual std::string InvokeActionForTesting(Action action,
+                                             const GURL& url) = 0;
+
+ protected:
+  // Return a serialized ClientSafeBrowsingReportRequest proto.
+  std::string CreateSafeBrowsingDownloadRecoveryReport(bool did_proceed,
+                                                       const GURL& url);
+
+  // Sends threat details to safe browsing backend.
+  // Since it only records download url and user's action (click through or,
+  // not), it isn't gated by extended_reporting. We should not put any extra
+  // information in this report.
+  void SendSerializedReport(const std::string& report);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_DANGER_PROMPT_H_