Trigger the Snippets Scheduler when Resuming Activities

Inform the scheduler on resuming activites, so fetching of new
snippets consider this event.

(There is a related CL that triggers a similar event for new tabs:
https://codereview.chromium.org/2592053004/)

BUG=676308

Review-Url: https://codereview.chromium.org/2599743002
Cr-Commit-Position: refs/heads/master@{#441768}

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

@@ -80,6 +80,8 @@ import org.chromium.chrome.browser.metrics.UmaUtils;
 import org.chromium.chrome.browser.multiwindow.MultiWindowUtils;
 import org.chromium.chrome.browser.ntp.NativePageAssassin;
 import org.chromium.chrome.browser.ntp.NewTabPageUma;
+import org.chromium.chrome.browser.ntp.snippets.SnippetsBridge;
+import org.chromium.chrome.browser.ntp.snippets.SnippetsConfig;
 import org.chromium.chrome.browser.omaha.OmahaClient;
 import org.chromium.chrome.browser.omnibox.AutocompleteController;
 import org.chromium.chrome.browser.partnercustomizations.HomepageManager;
@@ -431,6 +433,14 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
 
         mLocaleManager.setSnackbarManager(getSnackbarManager());
         mLocaleManager.startObservingPhoneChanges();
+
+        if (SnippetsConfig.isEnabled()) {
+            if (isWarmOnResume()) {
+                SnippetsBridge.notifySchedulerAboutWarmResume();
+            } else {
+                SnippetsBridge.notifySchedulerAboutColdStart();
+            }
+        }
     }
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/init/AsyncInitializationActivity.java

@@ -63,6 +63,11 @@ public abstract class AsyncInitializationActivity extends AppCompatActivity impl
     private long mLastUserInteractionTime;
     private boolean mIsTablet;
     private boolean mHadWarmStart;
+    private boolean mIsWarmOnResume;
+
+    // Stores whether the activity was not resumed yet. Always false after the
+    // first |onResume| call.
+    private boolean mFirstResumePending = true;
 
     public AsyncInitializationActivity() {
         mHandler = new Handler();
@@ -294,6 +299,8 @@ public abstract class AsyncInitializationActivity extends AppCompatActivity impl
         super.onResume();
         mNativeInitializationController.onResume();
         if (mLaunchBehindWorkaround != null) mLaunchBehindWorkaround.onResume();
+        mIsWarmOnResume = !mFirstResumePending || hadWarmStart();
+        mFirstResumePending = false;
     }
 
     @Override
@@ -408,6 +415,18 @@ public abstract class AsyncInitializationActivity extends AppCompatActivity impl
         return mHadWarmStart;
     }
 
+    /**
+     * This returns true if the activity was started warm (native library loaded and initialized) or
+     * if a cold starts have been completed by the time onResume is/will be called.
+     * This is useful to distinguish between the case where an already running instance of Chrome is
+     * being brought back to the foreground from the case where Chrome is started, in order to avoid
+     * contention on browser startup
+     * @return Whether the activity is warm in onResume.
+     */
+    public boolean isWarmOnResume() {
+        return mIsWarmOnResume;
+    }
+
     @Override
     public void onUserInteraction() {
         mLastUserInteractionTime = SystemClock.elapsedRealtime();

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetsBridge.java

@@ -179,6 +179,16 @@ public class SnippetsBridge implements SuggestionsSource {
         nativeOnNTPInitialized(mNativeSnippetsBridge);
     }
 
+    public static void notifySchedulerAboutWarmResume() {
+        SnippetsBridge snippetsBridge = new SnippetsBridge(Profile.getLastUsedProfile());
+        snippetsBridge.onActivityWarmResumed();
+    }
+
+    public static void notifySchedulerAboutColdStart() {
+        SnippetsBridge snippetsBridge = new SnippetsBridge(Profile.getLastUsedProfile());
+        snippetsBridge.onColdStart();
+    }
+
     public static void onSuggestionTargetVisited(int category, long visitTimeMs) {
         nativeOnSuggestionTargetVisited(category, visitTimeMs);
     }
@@ -202,6 +212,16 @@ public class SnippetsBridge implements SuggestionsSource {
         nativeFetch(mNativeSnippetsBridge, category, displayedSuggestionIds);
     }
 
+    private void onActivityWarmResumed() {
+        assert mNativeSnippetsBridge != 0;
+        nativeOnActivityWarmResumed(mNativeSnippetsBridge);
+    }
+
+    private void onColdStart() {
+        assert mNativeSnippetsBridge != 0;
+        nativeOnColdStart(mNativeSnippetsBridge);
+    }
+
     @CalledByNative
     private static List<SnippetArticle> createSuggestionList() {
         return new ArrayList<>();
@@ -302,6 +322,8 @@ public class SnippetsBridge implements SuggestionsSource {
             long nativeNTPSnippetsBridge, int category, int position);
     private native void nativeOnMoreButtonClicked(
             long nativeNTPSnippetsBridge, int category, int position);
+    private native void nativeOnActivityWarmResumed(long nativeNTPSnippetsBridge);
+    private native void nativeOnColdStart(long nativeNTPSnippetsBridge);
     private static native void nativeOnSuggestionTargetVisited(int category, long visitTimeMs);
     private static native void nativeOnNTPInitialized(long nativeNTPSnippetsBridge);
 }

chrome/browser/android/ntp/ntp_snippets_bridge.cc

@@ -408,6 +408,30 @@ void NTPSnippetsBridge::OnNTPInitialized(
   scheduler->OnNTPOpened();
 }
 
+void NTPSnippetsBridge::OnColdStart(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  ntp_snippets::RemoteSuggestionsScheduler* scheduler =
+      GetRemoteSuggestionsScheduler();
+  // TODO(fhorschig): Remove guard when https://crbug.com/678556 is resolved.
+  if (!scheduler) {
+    return;
+  }
+  scheduler->OnBrowserColdStart();
+}
+
+void NTPSnippetsBridge::OnActivityWarmResumed(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  ntp_snippets::RemoteSuggestionsScheduler* scheduler =
+      GetRemoteSuggestionsScheduler();
+  // TODO(fhorschig): Remove guard when https://crbug.com/678556 is resolved.
+  if (!scheduler) {
+    return;
+  }
+  scheduler->OnBrowserForegrounded();
+}
+
 NTPSnippetsBridge::~NTPSnippetsBridge() {}
 
 void NTPSnippetsBridge::OnNewSuggestions(Category category) {

chrome/browser/android/ntp/ntp_snippets_bridge.h

@@ -130,6 +130,10 @@ class NTPSnippetsBridge
 
   void OnNTPInitialized(JNIEnv* env,
                         const base::android::JavaParamRef<jobject>& obj);
+  void OnColdStart(JNIEnv* env,
+                   const base::android::JavaParamRef<jobject>& obj);
+  void OnActivityWarmResumed(JNIEnv* env,
+                             const base::android::JavaParamRef<jobject>& obj);
 
   static bool Register(JNIEnv* env);
 

components/ntp_snippets/remote/remote_suggestions_scheduler.h

@@ -13,7 +13,16 @@ namespace ntp_snippets {
 class RemoteSuggestionsScheduler {
  public:
   // External triggers to consider fetching content suggestions.
-  virtual void OnBrowserStartup() = 0;
+
+  // Called whenever chrome is started warm or the user switches to Chrome.
+  virtual void OnBrowserForegrounded() = 0;
+
+  // Called whenever chrome is cold started.
+  // To keep start ups fast, defer any work possible.
+  virtual void OnBrowserColdStart() = 0;
+
+  // Called whenever a new NTP is opened. This may be called on cold starts.
+  // So to keep start ups fast, defer heavy work for cold starts.
   virtual void OnNTPOpened() = 0;
 
   // Fetch content suggestions.

components/ntp_snippets/remote/scheduling_remote_suggestions_provider.cc

@@ -180,7 +180,15 @@ void SchedulingRemoteSuggestionsProvider::OnPersistentSchedulerWakeUp() {
   RefetchInTheBackground(/*callback=*/nullptr);
 }
 
-void SchedulingRemoteSuggestionsProvider::OnBrowserStartup() {
+void SchedulingRemoteSuggestionsProvider::OnBrowserForegrounded() {
+  // TODO(jkrcal): Consider that this is called whenever we open or return to an
+  // Activity. Therefore, keep work light for fast start up calls.
+  // TODO(jkrcal): Implement.
+}
+
+void SchedulingRemoteSuggestionsProvider::OnBrowserColdStart() {
+  // TODO(fhorschig|jkrcal): Consider that work here must be kept light for fast
+  // cold start ups.
   // TODO(jkrcal): Implement.
 }
 

components/ntp_snippets/remote/scheduling_remote_suggestions_provider.h

@@ -70,7 +70,8 @@ class SchedulingRemoteSuggestionsProvider final
   // RemoteSuggestionsScheduler implementation.
   void RescheduleFetching() override;
   void OnPersistentSchedulerWakeUp() override;
-  void OnBrowserStartup() override;
+  void OnBrowserForegrounded() override;
+  void OnBrowserColdStart() override;
   void OnNTPOpened() override;
 
   // RemoteSuggestionsProvider implementation.