Reland "Add WebApp.Preinstalled.UninstallAndReplaceCount UMA histogram"

This reverts commit e2bb0435.

Reason for revert:
Original revert did not fix the issue. Real fix was:
https://chromium-review.googlesource.com/c/chromium/src/+/2566814

Original change's description:
> Revert "Add WebApp.Preinstalled.UninstallAndReplaceCount UMA histogram"
>
> This reverts commit 1ca3c153.
>
> Reason for revert:
> Needed to land parent CL revert: https://chromium-review.googlesource.com/c/chromium/src/+/2567511
>
> Original change's description:
> > Add WebApp.Preinstalled.UninstallAndReplaceCount UMA histogram
> >
> > This CL adds metrics for how often preinstalled web apps migrate and
> > remove an existing app install.
> >
> > This data is useful to monitor rollouts of default web apps that are
> > replacing old Chrome apps to ensure the migration is happening as
> > expected.
> >
> > Bug: 809304, 1058265
> > Change-Id: Ie9edb4a1cf89e84d7e56a20bad028dd8ea1aeb07
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2561999
> > Commit-Queue: Alan Cutter <alancutter@chromium.org>
> > Reviewed-by: Glen Robertson <glenrob@chromium.org>
> > Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#832148}
>
> TBR=rkaplow@chromium.org,alancutter@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com,glenrob@chromium.org
>
> Change-Id: I46c1a678e09111d210d1385bdb17ecc4fcabb093
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 809304
> Bug: 1058265
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567056
> Reviewed-by: Alan Cutter <alancutter@chromium.org>
> Commit-Queue: Alan Cutter <alancutter@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#832227}

TBR=rkaplow@chromium.org,alancutter@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com,glenrob@chromium.org

Bug: 809304
Bug: 1058265
Change-Id: I1139aa9380a809a4f96ab5664aa279973a60a788
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567281
Commit-Queue: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Alan Cutter <alancutter@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Glen Robertson <glenrob@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832681}

chrome/browser/web_applications/external_web_app_manager.cc

@@ -18,7 +18,7 @@
 #include "base/files/file_util.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/json/json_reader.h"
-#include "base/metrics/histogram_functions.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/no_destructor.h"
 #include "base/path_service.h"
 #include "base/stl_util.h"
@@ -219,6 +219,8 @@ const char* ExternalWebAppManager::kHistogramDisabledCount =
     "WebApp.Preinstalled.DisabledCount";
 const char* ExternalWebAppManager::kHistogramConfigErrorCount =
     "WebApp.Preinstalled.ConfigErrorCount";
+const char* ExternalWebAppManager::kHistogramUninstallAndReplaceCount =
+    "WebApp.Preinstalled.UninstallAndReplaceCount";
 
 void ExternalWebAppManager::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
@@ -354,12 +356,12 @@ void ExternalWebAppManager::PostProcessConfigs(ConsumeInstallOptions callback,
     debug_info_->enabled_configs = parsed_configs.options_list;
   }
 
-  base::UmaHistogramCounts100(ExternalWebAppManager::kHistogramEnabledCount,
-                              parsed_configs.options_list.size());
-  base::UmaHistogramCounts100(ExternalWebAppManager::kHistogramDisabledCount,
-                              disabled_count);
-  base::UmaHistogramCounts100(ExternalWebAppManager::kHistogramConfigErrorCount,
-                              parsed_configs.errors.size());
+  UMA_HISTOGRAM_COUNTS_100(ExternalWebAppManager::kHistogramEnabledCount,
+                           parsed_configs.options_list.size());
+  UMA_HISTOGRAM_COUNTS_100(ExternalWebAppManager::kHistogramDisabledCount,
+                           disabled_count);
+  UMA_HISTOGRAM_COUNTS_100(ExternalWebAppManager::kHistogramConfigErrorCount,
+                           parsed_configs.errors.size());
 
   std::move(callback).Run(parsed_configs.options_list);
 }
@@ -386,10 +388,16 @@ void ExternalWebAppManager::OnExternalWebAppsSynchronized(
       prefs::kWebAppsLastPreinstallSynchronizeVersion,
       version_info::GetMajorVersionNumber());
 
+  size_t uninstall_and_replace_count = 0;
   for (const auto& url_and_result : install_results) {
-    base::UmaHistogramEnumeration("Webapp.InstallResult.Default",
-                                  url_and_result.second.code);
+    UMA_HISTOGRAM_ENUMERATION("Webapp.InstallResult.Default",
+                              url_and_result.second.code);
+    if (url_and_result.second.did_uninstall_and_replace)
+      ++uninstall_and_replace_count;
   }
+  UMA_HISTOGRAM_COUNTS_100(
+      ExternalWebAppManager::kHistogramUninstallAndReplaceCount,
+      uninstall_and_replace_count);
 
   if (callback) {
     std::move(callback).Run(std::move(install_results),

chrome/browser/web_applications/external_web_app_manager.h

@@ -51,6 +51,7 @@ class ExternalWebAppManager {
   static const char* kHistogramEnabledCount;
   static const char* kHistogramDisabledCount;
   static const char* kHistogramConfigErrorCount;
+  static const char* kHistogramUninstallAndReplaceCount;
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 

chrome/browser/web_applications/external_web_app_migration_browsertest.cc

@@ -246,6 +246,7 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest,
     EXPECT_TRUE(IsExtensionAppInstalled());
 
     {
+      base::HistogramTester histograms;
       extensions::TestExtensionRegistryObserver uninstall_observer(
           extensions::ExtensionRegistry::Get(profile()));
 
@@ -256,6 +257,8 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest,
           uninstall_observer.WaitForExtensionUninstalled();
       EXPECT_EQ(uninstalled_app->id(), kExtensionId);
       EXPECT_FALSE(IsExtensionAppInstalled());
+      histograms.ExpectUniqueSample(
+          ExternalWebAppManager::kHistogramUninstallAndReplaceCount, 1, 1);
     }
   }
 
@@ -272,6 +275,7 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest,
 
   // Re-run migration.
   {
+    base::HistogramTester histograms;
     base::AutoReset<bool> testing_scope =
         SetExternalAppInstallFeatureAlwaysEnabledForTesting();
     ASSERT_TRUE(IsExternalAppInstallFeatureEnabled(kMigrationFlag));
@@ -286,6 +290,8 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest,
         uninstall_observer.WaitForExtensionUninstalled();
     EXPECT_EQ(uninstalled_app->id(), kExtensionId);
     EXPECT_FALSE(IsExtensionAppInstalled());
+    histograms.ExpectUniqueSample(
+        ExternalWebAppManager::kHistogramUninstallAndReplaceCount, 1, 1);
   }
 }
 
@@ -341,6 +347,7 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest, MigratePreferences) {
     EXPECT_TRUE(IsExtensionAppInstalled());
 
     {
+      base::HistogramTester histograms;
       extensions::TestExtensionRegistryObserver uninstall_observer(
           extensions::ExtensionRegistry::Get(profile()));
 
@@ -351,6 +358,8 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest, MigratePreferences) {
           uninstall_observer.WaitForExtensionUninstalled();
       EXPECT_EQ(uninstalled_app->id(), kExtensionId);
       EXPECT_FALSE(IsExtensionAppInstalled());
+      histograms.ExpectUniqueSample(
+          ExternalWebAppManager::kHistogramUninstallAndReplaceCount, 1, 1);
     }
   }
 
@@ -494,6 +503,8 @@ IN_PROC_BROWSER_TEST_F(ExternalWebAppMigrationBrowserTest,
           ExternalWebAppManager::kHistogramDisabledCount, 0, 1);
       histograms.ExpectUniqueSample(
           ExternalWebAppManager::kHistogramConfigErrorCount, 0, 1);
+      histograms.ExpectUniqueSample(
+          ExternalWebAppManager::kHistogramUninstallAndReplaceCount, 1, 1);
     }
   }
 }

tools/metrics/histograms/histograms_xml/others/histograms.xml

@@ -17040,6 +17040,17 @@ regressions. -->
   </summary>
 </histogram>
 
+<histogram name="WebApp.Preinstalled.UninstallAndReplaceCount" units="apps"
+    expires_after="2021-04-01">
+  <owner>alancutter@chromium.org</owner>
+  <owner>desktop-pwas-team@google.com</owner>
+  <summary>
+    Records how many preinstalled web app installations uninstalled and replaced
+    an old default app (web app or Chrome app). This corresponds to the
+    &quot;uninstall_and_replace&quot; field in preinstalled web app configs.
+  </summary>
+</histogram>
+
 <histogram name="WebApp.Shortcuts.Creation.Result"
     enum="ShortcutsCreationResult" expires_after="M93">
   <owner>phillis@chromium.org</owner>