Add number of NTP tabs on start and resume histograms

Bug: 1136539
Change-Id: I1bd58115d0d2c0f4502049040181227bcee85d4c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2461709
Commit-Queue: Ganggui Tang <gogerald@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Auto-Submit: Ganggui Tang <gogerald@chromium.org>
Cr-Commit-Position: refs/heads/master@{#816587}

ios/chrome/app/application_delegate/BUILD.gn

@@ -203,6 +203,7 @@ source_set("application_delegate_internal") {
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/main",
     "//ios/chrome/browser/ui/main:scene",
+    "//ios/chrome/browser/ui/ntp:util",
     "//ios/chrome/browser/ui/safe_mode",
     "//ios/chrome/browser/ui/util",
     "//ios/chrome/browser/ui/util:multiwindow_util",

ios/chrome/app/application_delegate/metrics_mediator.mm

@@ -32,6 +32,7 @@
 #import "ios/chrome/browser/ui/main/browser_interface_provider.h"
 #import "ios/chrome/browser/ui/main/connection_information.h"
 #import "ios/chrome/browser/ui/main/scene_state.h"
+#import "ios/chrome/browser/ui/ntp/ntp_util.h"
 #import "ios/chrome/browser/web_state_list/web_state_list.h"
 #include "ios/chrome/common/app_group/app_group_metrics_mainapp.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
@@ -110,6 +111,10 @@ using metrics_mediator::kAppEnteredBackgroundDateKey;
 + (void)recordNumTabAtStartup:(int)numTabs;
 // Logs the number of tabs with UMAHistogramCount100 and allows testing.
 + (void)recordNumTabAtResume:(int)numTabs;
+// Logs the number of NTP tabs with UMAHistogramCount100 and allows testing.
++ (void)recordNumNTPTabAtStartup:(int)numTabs;
+// Logs the number of NTP tabs with UMAHistogramCount100 and allows testing.
++ (void)recordNumNTPTabAtResume:(int)numTabs;
 
 @end
 
@@ -150,6 +155,7 @@ using metrics_mediator::kAppEnteredBackgroundDateKey;
             (id<StartupInformation>)startupInformation
                                connectedScenes:(NSArray<SceneState*>*)scenes {
   int numTabs = 0;
+  int numNTPTabs = 0;
   for (SceneState* scene in scenes) {
     if (!scene.interfaceProvider) {
       // The scene might not yet be initiated.
@@ -157,14 +163,23 @@ using metrics_mediator::kAppEnteredBackgroundDateKey;
       // counted in sessions instead of scenes.
       continue;
     }
-    numTabs += scene.interfaceProvider.mainInterface.browser->GetWebStateList()
-                   ->count();
+
+    const WebStateList* web_state_list =
+        scene.interfaceProvider.mainInterface.browser->GetWebStateList();
+    numTabs += web_state_list->count();
+    for (int i = 0; i < web_state_list->count(); i++) {
+      if (IsURLNewTabPage(web_state_list->GetWebStateAt(i)->GetVisibleURL())) {
+        numNTPTabs++;
+      }
+    }
   }
 
   if (startupInformation.isColdStart) {
     [self recordNumTabAtStartup:numTabs];
+    [self recordNumNTPTabAtStartup:numNTPTabs];
   } else {
     [self recordNumTabAtResume:numTabs];
+    [self recordNumNTPTabAtResume:numNTPTabs];
   }
 
   if (UIAccessibilityIsVoiceOverRunning()) {
@@ -427,6 +442,14 @@ using metrics_mediator::kAppEnteredBackgroundDateKey;
   base::UmaHistogramCounts100("Tabs.CountAtResume", numTabs);
 }
 
++ (void)recordNumNTPTabAtStartup:(int)numTabs {
+  base::UmaHistogramCounts100("Tabs.NTPCountAtStartup", numTabs);
+}
+
++ (void)recordNumNTPTabAtResume:(int)numTabs {
+  base::UmaHistogramCounts100("Tabs.NTPCountAtResume", numTabs);
+}
+
 - (void)setBreakpadUploadingEnabled:(BOOL)enableUploading {
   breakpad_helper::SetUploadingEnabled(enableUploading);
 }

ios/chrome/app/application_delegate/metrics_mediator_testing.h

@@ -15,6 +15,8 @@
 - (BOOL)isMetricsReportingEnabledWifiOnly;
 + (void)recordNumTabAtStartup:(int)numTabs;
 + (void)recordNumTabAtResume:(int)numTabs;
++ (void)recordNumNTPTabAtStartup:(int)numTabs;
++ (void)recordNumNTPTabAtResume:(int)numTabs;
 @end
 
 #endif  // IOS_CHROME_APP_APPLICATION_DELEGATE_METRICS_MEDIATOR_TESTING_H_

ios/chrome/app/application_delegate/metrics_mediator_unittest.mm

@@ -10,6 +10,7 @@
 #include "components/metrics/metrics_service.h"
 #import "ios/chrome/app/application_delegate/startup_information.h"
 #include "ios/chrome/browser/application_context.h"
+#include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/main/test_browser.h"
 #import "ios/chrome/browser/metrics/previous_session_info.h"
 #import "ios/chrome/browser/metrics/previous_session_info_private.h"
@@ -132,36 +133,55 @@ TEST_F(MetricsMediatorTest, connectionTypeChanged) {
 
 // A block that takes as arguments the caller and the arguments from
 // UserActivityHandler +handleStartupParameters and returns nothing.
-typedef void (^logLaunchMetricsBlock)(id, const char*, int);
+typedef void (^LogLaunchMetricsBlock)(id, const char*, int);
 
 class MetricsMediatorLogLaunchTest : public PlatformTest {
  protected:
-  MetricsMediatorLogLaunchTest() : has_been_called_(FALSE) {}
+  MetricsMediatorLogLaunchTest()
+      : num_tabs_has_been_called_(FALSE),
+        num_ntp_tabs_has_been_called_(FALSE) {}
 
   void initiateMetricsMediator(BOOL coldStart, int tabCount) {
-    swizzle_block_ = [^(id self, int numTab) {
-      has_been_called_ = YES;
+    num_tabs_swizzle_block_ = [^(id self, int numTab) {
+      num_tabs_has_been_called_ = YES;
+      // Tests.
+      EXPECT_EQ(tabCount, numTab);
+    } copy];
+    num_ntp_tabs_swizzle_block_ = [^(id self, int numTab) {
+      num_ntp_tabs_has_been_called_ = YES;
       // Tests.
       EXPECT_EQ(tabCount, numTab);
     } copy];
     if (coldStart) {
-      uma_histogram_swizzler_.reset(new ScopedBlockSwizzler(
+      tabs_uma_histogram_swizzler_.reset(new ScopedBlockSwizzler(
           [MetricsMediator class], @selector(recordNumTabAtStartup:),
-          swizzle_block_));
+          num_tabs_swizzle_block_));
+      ntp_tabs_uma_histogram_swizzler_.reset(new ScopedBlockSwizzler(
+          [MetricsMediator class], @selector(recordNumNTPTabAtStartup:),
+          num_ntp_tabs_swizzle_block_));
     } else {
-      uma_histogram_swizzler_.reset(new ScopedBlockSwizzler(
+      tabs_uma_histogram_swizzler_.reset(new ScopedBlockSwizzler(
           [MetricsMediator class], @selector(recordNumTabAtResume:),
-          swizzle_block_));
+          num_tabs_swizzle_block_));
+      ntp_tabs_uma_histogram_swizzler_.reset(new ScopedBlockSwizzler(
+          [MetricsMediator class], @selector(recordNumNTPTabAtResume:),
+          num_ntp_tabs_swizzle_block_));
     }
   }
 
-  void verifySwizzleHasBeenCalled() { EXPECT_TRUE(has_been_called_); }
+  void verifySwizzleHasBeenCalled() {
+    EXPECT_TRUE(num_tabs_has_been_called_);
+    EXPECT_TRUE(num_ntp_tabs_has_been_called_);
+  }
 
   web::WebTaskEnvironment task_environment_;
   NSArray<FakeSceneState*>* connected_scenes_;
-  __block BOOL has_been_called_;
-  logLaunchMetricsBlock swizzle_block_;
-  std::unique_ptr<ScopedBlockSwizzler> uma_histogram_swizzler_;
+  __block BOOL num_tabs_has_been_called_;
+  __block BOOL num_ntp_tabs_has_been_called_;
+  LogLaunchMetricsBlock num_tabs_swizzle_block_;
+  LogLaunchMetricsBlock num_ntp_tabs_swizzle_block_;
+  std::unique_ptr<ScopedBlockSwizzler> tabs_uma_histogram_swizzler_;
+  std::unique_ptr<ScopedBlockSwizzler> ntp_tabs_uma_histogram_swizzler_;
   std::set<std::unique_ptr<TestBrowser>> browsers_;
 };
 
@@ -173,9 +193,12 @@ TEST_F(MetricsMediatorLogLaunchTest,
   initiateMetricsMediator(coldStart, 23);
   // 23 tabs across three scenes.
   connected_scenes_ = [FakeSceneState sceneArrayWithCount:3];
-  [connected_scenes_[0] appendWebStatesWithURL:GURL() count:9];
-  [connected_scenes_[1] appendWebStatesWithURL:GURL() count:9];
-  [connected_scenes_[2] appendWebStatesWithURL:GURL() count:5];
+  [connected_scenes_[0] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:9];
+  [connected_scenes_[1] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:9];
+  [connected_scenes_[2] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:5];
   // Mark one of the scenes as active.
   connected_scenes_[0].activationLevel = SceneActivationLevelForegroundActive;
 
@@ -211,11 +234,15 @@ TEST_F(MetricsMediatorLogLaunchTest, logLaunchMetricsNoBackgroundDate) {
   initiateMetricsMediator(coldStart, 32);
   // 32 tabs across five scenes.
   connected_scenes_ = [FakeSceneState sceneArrayWithCount:5];
-  [connected_scenes_[0] appendWebStatesWithURL:GURL() count:8];
-  [connected_scenes_[1] appendWebStatesWithURL:GURL() count:8];
+  [connected_scenes_[0] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:8];
+  [connected_scenes_[1] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:8];
   // Scene 2 has zero tabs.
-  [connected_scenes_[3] appendWebStatesWithURL:GURL() count:8];
-  [connected_scenes_[4] appendWebStatesWithURL:GURL() count:8];
+  [connected_scenes_[3] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:8];
+  [connected_scenes_[4] appendWebStatesWithURL:GURL(kChromeUINewTabURL)
+                                         count:8];
 
   id startupInformation =
       [OCMockObject mockForProtocol:@protocol(StartupInformation)];

tools/metrics/histograms/histograms_xml/tab/histograms.xml

@@ -1218,6 +1218,20 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
   </summary>
 </histogram>
 
+<histogram name="Tabs.NTPCountAtResume" units="tabs" expires_after="M95">
+  <owner>gogerald@chromium.org</owner>
+  <owner>nasims@google.com</owner>
+  <summary>
+    [iOS] The number of NTP tabs open when the app comes out of the background.
+  </summary>
+</histogram>
+
+<histogram name="Tabs.NTPCountAtStartup" units="tabs" expires_after="M95">
+  <owner>gogerald@chromium.org</owner>
+  <owner>nasims@google.com</owner>
+  <summary>[iOS] The number of NTP tabs open at cold launch.</summary>
+</histogram>
+
 <histogram name="Tabs.NumberOfTabsOnResume" units="tabs" expires_after="never">
 <!-- expires-never: https://crbug.com/966137 -->