Notify metrics when WebLayer's activity enters foreground and background.

Bug: 1096390
Change-Id: I83d9062895cdc29c6f21b815105123b376472085
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2251054
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#780181}

weblayer/browser/browser_impl.cc

@@ -29,6 +29,9 @@
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/json/json_writer.h"
+#include "components/metrics/metrics_service.h"
+#include "components/ukm/ukm_service.h"
+#include "weblayer/browser/android/metrics/weblayer_metrics_service_client.h"
 #include "weblayer/browser/browser_process.h"
 #include "weblayer/browser/java/jni/BrowserImpl_jni.h"
 #endif
@@ -48,6 +51,43 @@ std::vector<BrowserImpl*>& GetBrowsers() {
   return *browsers;
 }
 
+#if defined(OS_ANDROID)
+void UpdateMetricsService() {
+  static bool s_foreground = false;
+  bool foreground = false;
+  for (auto* browser : GetBrowsers()) {
+    if (browser->fragment_resumed()) {
+      // We need at least one browser to be foreground.
+      foreground = true;
+      break;
+    }
+  }
+
+  if (foreground == s_foreground)
+    return;
+
+  s_foreground = foreground;
+
+  auto* metrics_service =
+      WebLayerMetricsServiceClient::GetInstance()->GetMetricsService();
+  if (metrics_service) {
+    if (foreground)
+      metrics_service->OnAppEnterForeground();
+    else
+      metrics_service->OnAppEnterBackground();
+  }
+
+  auto* ukm_service =
+      WebLayerMetricsServiceClient::GetInstance()->GetUkmService();
+  if (ukm_service) {
+    if (foreground)
+      ukm_service->OnAppEnterForeground();
+    else
+      ukm_service->OnAppEnterBackground();
+  }
+}
+#endif  // defined(OS_ANDROID)
+
 }  // namespace
 
 // static
@@ -213,6 +253,16 @@ void BrowserImpl::OnFragmentStart(JNIEnv* env) {
   FeatureListCreator::GetInstance()->OnBrowserFragmentStarted();
 }
 
+void BrowserImpl::OnFragmentResume(JNIEnv* env) {
+  fragment_resumed_ = true;
+  UpdateMetricsService();
+}
+
+void BrowserImpl::OnFragmentPause(JNIEnv* env) {
+  fragment_resumed_ = false;
+  UpdateMetricsService();
+}
+
 #endif
 
 std::vector<uint8_t> BrowserImpl::GetMinimalPersistenceState(

weblayer/browser/browser_impl.h

@@ -80,6 +80,10 @@ class BrowserImpl : public Browser {
           j_minimal_persistence_state);
   void WebPreferencesChanged(JNIEnv* env);
   void OnFragmentStart(JNIEnv* env);
+  void OnFragmentResume(JNIEnv* env);
+  void OnFragmentPause(JNIEnv* env);
+
+  bool fragment_resumed() { return fragment_resumed_; }
 #endif
 
   // Used in tests to specify a non-default max (0 means use the default).
@@ -130,6 +134,7 @@ class BrowserImpl : public Browser {
   base::FilePath GetBrowserPersisterDataPath();
 
 #if defined(OS_ANDROID)
+  bool fragment_resumed_ = false;
   base::android::ScopedJavaGlobalRef<jobject> java_impl_;
 #endif
   base::ObserverList<BrowserObserver> browser_observers_;

weblayer/browser/java/org/chromium/weblayer_private/BrowserImpl.java

@@ -468,10 +468,12 @@ public class BrowserImpl extends IBrowser.Stub {
     public void onFragmentResume() {
         mFragmentResumed = true;
         WebLayerAccessibilityUtil.get().onBrowserResumed();
+        BrowserImplJni.get().onFragmentResume(mNativeBrowser);
     }
 
     public void onFragmentPause() {
         mFragmentResumed = false;
+        BrowserImplJni.get().onFragmentPause(mNativeBrowser);
     }
 
     public boolean isStarted() {
@@ -535,5 +537,7 @@ public class BrowserImpl extends IBrowser.Stub {
                 byte[] persistenceCryptoKey, byte[] minimalPersistenceState);
         void webPreferencesChanged(long nativeBrowserImpl);
         void onFragmentStart(long nativeBrowserImpl);
+        void onFragmentResume(long nativeBrowserImpl);
+        void onFragmentPause(long nativeBrowserImpl);
     }
 }