Add some histograms to see how often users click through blocking pages....

chrome/browser/safe_browsing/safe_browsing_blocking_page.cc

Index: chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
===================================================================
--- chrome/browser/safe_browsing/safe_browsing_blocking_page.cc	(revision 14518)
+++ chrome/browser/safe_browsing/safe_browsing_blocking_page.cc	(working copy)
@@ -6,6 +6,7 @@
 
 #include "chrome/browser/safe_browsing/safe_browsing_blocking_page.h"
 
+#include "base/histogram.h"
 #include "base/string_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/dom_operation_notification_details.h"
@@ -49,6 +50,21 @@
 static const char* const kProceedCommand = "proceed";
 static const char* const kTakeMeBackCommand = "takeMeBack";
 
+namespace {
+
+enum SafeBrowsingBlockingPageEvent {
+  SHOW,
+  PROCEED,
+  DONT_PROCEED,
+};
+
+void RecordSafeBrowsingBlockingPageStats(SafeBrowsingBlockingPageEvent event) {
+  static LinearHistogram histogram("interstial.safe_browsing", 0, 2, 4);

[jar (doing other things), 2009/04/27 00:20:49]

Looking at the unit test, and other examples, the more common set of numbers
(for min, max, count) would be:

1, N, N+1

In this case, perchance:

1, 3, 4 would be best.

Also note, that it is good to leave one additional bucket unused, as buckets are
defined as having a min and max value.  Hence the "top bucket" is always "N no
infinity".  This can cause problems if you later decide to add another bucket,
and then you have a distinct "N to N+1" and "N to infinity" coming from
different flavors of the histogram.

+  histogram.SetFlags(kUmaTargetedHistogramFlag);
+  histogram.Add(event);
+}
+
+}  // namespace
 // static
 SafeBrowsingBlockingPageFactory* SafeBrowsingBlockingPage::factory_ = NULL;
 
@@ -83,6 +99,7 @@
       sb_service_(sb_service),
       is_main_frame_(IsMainPage(unsafe_resources)),
       unsafe_resources_(unsafe_resources) {
+  RecordSafeBrowsingBlockingPageStats(SHOW);
   if (!is_main_frame_) {
     navigation_entry_index_to_remove_ =
         tab()->controller().last_committed_entry_index();
@@ -362,6 +379,8 @@
 }
 
 void SafeBrowsingBlockingPage::Proceed() {
+  RecordSafeBrowsingBlockingPageStats(PROCEED);
+
   NotifySafeBrowsingService(sb_service_, unsafe_resources_, true);
 
   // Check to see if some new notifications of unsafe resources have been
@@ -387,6 +406,8 @@
 }
 
 void SafeBrowsingBlockingPage::DontProceed() {
+  RecordSafeBrowsingBlockingPageStats(DONT_PROCEED);
+
   NotifySafeBrowsingService(sb_service_, unsafe_resources_, false);
 
   // The user does not want to proceed, clear the queued unsafe resources