Isolate initiation counts for downloads to their own histograms and improve

chrome/browser/download/download_resource_throttle.cc

Index: chrome/browser/download/download_resource_throttle.cc
diff --git a/chrome/browser/download/download_resource_throttle.cc b/chrome/browser/download/download_resource_throttle.cc
index 87d41dc7939feb8e815e525c660bc0e22139db90..2e7728f8bfa0d0a98a30d950f1b82280dfe5e496 100644
--- a/chrome/browser/download/download_resource_throttle.cc
+++ b/chrome/browser/download/download_resource_throttle.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/download/download_resource_throttle.h"
 
 #include "base/bind.h"
+#include "chrome/browser/download/download_util.h"
 #include "content/public/browser/resource_throttle_controller.h"
 
 DownloadResourceThrottle::DownloadResourceThrottle(
@@ -40,6 +41,12 @@ void DownloadResourceThrottle::WillReadRequest(bool* defer) {
 
 void DownloadResourceThrottle::ContinueDownload(bool allow) {
   request_allowed_ = allow;
+  if (allow) {
+      download_util::RecordDownloadSource(

[darin (slow to review), 2012/02/10 23:47:28]

nit: indentation

You are counting on the fact that ContinueDownload only gets called once and
that DownloadResourceThrottle is only used for downloads initiated by
navigation, right?  Those are pretty obvious pre-conditions for this code, so
maybe it is fine to just assume that.  Otherwise, maybe it is worth a comment or
even an assertion, in case someone extends this class or uses it in another
context later.  I suppose the INITIATED_BY_NAVIGATION flag could be passed to
the DownloadResourceThrottle constructor if need be.

[Randy Smith (Not in Mondays), 2012/02/12 19:19:00]

Done.

+          download_util::INITIATED_BY_NAVIGATION);
+  } else {
+      download_util::RecordDownloadCount(download_util::BLOCKED_BY_THROTTLING);
+  }
 
   if (request_deferred_) {
     if (allow) {