Add UMA to track the extensions (and friends) which have been allowed in

chrome/browser/extensions/installed_loader.cc

Index: chrome/browser/extensions/installed_loader.cc
diff --git a/chrome/browser/extensions/installed_loader.cc b/chrome/browser/extensions/installed_loader.cc
index 240616074637dd2a589c2a1fb281b352741c1482..d1236038e54de3899f8538363caf1d7a3307c5b8 100644
--- a/chrome/browser/extensions/installed_loader.cc
+++ b/chrome/browser/extensions/installed_loader.cc
@@ -14,6 +14,7 @@
 #include "chrome/browser/extensions/extension_action_manager.h"
 #include "chrome/browser/extensions/extension_error_reporter.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/api/managed_mode_private/managed_mode_handler.h"
@@ -191,6 +192,7 @@ void InstalledLoader::LoadAllExtensions() {
 
   base::TimeTicks start_time = base::TimeTicks::Now();
 
+  Profile* profile = extension_service_->profile();
   scoped_ptr<ExtensionPrefs::ExtensionsInfo> extensions_info(
       extension_prefs_->GetInstalledExtensionsInfo());
 
@@ -230,7 +232,7 @@ void InstalledLoader::LoadAllExtensions() {
         ExtensionErrorReporter::GetInstance()->ReportLoadError(
             info->extension_path,
             error,
-            extension_service_->profile(),
+            profile,
             false);  // Be quiet.
         continue;
       }
@@ -259,10 +261,49 @@ void InstalledLoader::LoadAllExtensions() {
   UMA_HISTOGRAM_COUNTS_100("Extensions.ManifestReloadNeedsRelocalization",
                            reload_reason_counts[NEEDS_RELOCALIZATION]);
 
-  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadAll",
-                           extension_registry_->enabled_extensions().size());
-  UMA_HISTOGRAM_COUNTS_100("Extensions.Disabled",
-                           extension_registry_->disabled_extensions().size());
+  const ExtensionSet& enabled = extension_registry_->enabled_extensions();
+  const ExtensionSet& disabled = extension_registry_->disabled_extensions();

[Devlin, 2014/05/09 22:45:25]

why store disabled?  Only used on line 268, right?

[not at google - send to devlin, 2014/05/09 22:58:56]

harmony. but I can revert.

+
+  UMA_HISTOGRAM_COUNTS_100("Extensions.LoadAll", enabled.size());
+  UMA_HISTOGRAM_COUNTS_100("Extensions.Disabled", disabled.size());
+
+  // Gather stats about the extensions which have/have-not been enabled for
+  // incognito and file access in chrome://extensions.
+  int incognito = 0, not_incognito = 0, file_access = 0, not_file_access = 0;

[Devlin, 2014/05/09 22:45:25]

chrome style: one variable per line.

[Devlin, 2014/05/09 22:45:25]

nit: seems like these are conceptually a size_t.

[not at google - send to devlin, 2014/05/09 22:58:56]

Done, though I'm not totally sure about this one.

+
+  for (ExtensionSet::const_iterator it = enabled.begin();

[Devlin, 2014/05/09 22:45:25]

Do we only care about enabled extensions?

[not at google - send to devlin, 2014/05/09 22:58:56]

Yeah I was thinking about this. I wasn't entirely certain and it could go either
way (i.e. the data should be fairly similar, just more exaggerated). Ultimately
I'm interested in the number of extensions each startup which the user has opted
into running in incognito mode or file:// URLs, and that means enabled.

+       it != enabled.end();
+       ++it) {
+    const Extension& e = **it;
+
+    // Skip unpacked extensions because they get file access up-front, and
+    // the data isn't useful. Skip anything that doesn't appear in settings.
+    if (e.location() == Manifest::UNPACKED ||
+        !e.ShouldDisplayInExtensionSettings()) {
+      continue;
+    }
+
+    if (e.can_be_incognito_enabled()) {
+      if (util::IsIncognitoEnabled(e.id(), profile)) {
+        ++incognito;
+      } else {

[Devlin, 2014/05/09 22:45:25]

nit: no braces around single-line ifs/elses

[not at google - send to devlin, 2014/05/09 22:58:56]

haha

If you insist.

+        ++not_incognito;
+      }
+    }
+
+    if (e.wants_file_access()) {
+      if (util::AllowFileAccess(e.id(), profile)) {
+        ++file_access;
+      } else {
+        ++not_file_access;
+      }
+    }
+  }
+
+  UMA_HISTOGRAM_COUNTS_100("Extensions.IncognitoAllowed", incognito);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.IncognitoNotAllowed", not_incognito);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.FileAccessAllowed", file_access);
+  UMA_HISTOGRAM_COUNTS_100("Extensions.FileAccessNotAllowed", not_file_access);
 
   UMA_HISTOGRAM_TIMES("Extensions.LoadAllTime",
                       base::TimeTicks::Now() - start_time);