customtabs: UMA histogram tracking whether clients call warmup().

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
index f3a6d0af9083a8d470f35df3a05ca4fedf19d128..c25117dd114115a97aa802e1eabeffe5e33c086e 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabsConnection.java
@@ -27,6 +27,7 @@ import android.support.customtabs.ICustomTabsCallback;
 import android.support.customtabs.ICustomTabsService;
 import android.text.TextUtils;
 import android.util.SparseArray;
+import android.util.SparseBooleanArray;
 import android.view.WindowManager;
 
 import org.chromium.base.FieldTrialList;
@@ -79,6 +80,13 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
     private static final int GOOD_PREDICTION = 1;
     private static final int BAD_PREDICTION = 2;
     private static final int PREDICTION_STATUS_COUNT = 3;
+    // Values for the "CustomTabs.CalledWarmup" UMA histogram. Append-only.

[pasko, 2015/09/03 18:02:19]

nittynit: empty line above would look nicer

[Benoit L, 2015/09/29 09:04:23]

Ack.

+    private static final int NO_SESSION_NO_WARMUP = 0;
+    private static final int NO_SESSION_WARMUP = 1;
+    private static final int SESSION_NO_WARMUP_ALREADY_CALLED = 2;
+    private static final int SESSION_NO_WARMUP_NOT_CALLED = 3;
+    private static final int SESSION_WARMUP = 4;
+    private static final int SESSION_WARMUP_COUNT = 5;
 
     private static AtomicReference<CustomTabsConnection> sInstance =
             new AtomicReference<CustomTabsConnection>();
@@ -196,6 +204,8 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
     // Prediction tracking is done by UID and not by session, since a
     // mis-behaving application can create a large number of sessions.
     private SparseArray<PredictionStats> mUidToPredictionsStats = new SparseArray<>();
+    // Whether a client application has called warmup() in this instance lifetime.
+    private SparseBooleanArray mUidHasCalledWarmup = new SparseBooleanArray();
 
     /**
      * <strong>DO NOT CALL</strong>
@@ -261,6 +271,11 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
     public boolean warmup(long flags) {
         // Here and in mayLaunchUrl(), don't do expensive work for background applications.
         if (!isCallerForegroundOrSelf()) return false;
+
+        synchronized (mLock) {
+            mUidHasCalledWarmup.put(Binder.getCallingUid(), true);
+        }
+
         if (!mWarmupHasBeenCalled.compareAndSet(false, true)) return true;
         // The call is non-blocking and this must execute on the UI thread, post a task.
         ThreadUtils.postOnUiThread(new Runnable() {
@@ -384,11 +399,16 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
     void registerLaunch(IBinder session, String url) {
         int outcome;
         long elapsedTimeMs = -1;
+        boolean hasValidSession = false;
+        boolean hasUidCalledWarmup = false;
         synchronized (mLock) {
             SessionParams sessionParams = mSessionParams.get(session);
             if (sessionParams == null) {
                 outcome = NO_PREDICTION;
             } else {
+                hasValidSession = true;
+                hasUidCalledWarmup = mUidHasCalledWarmup.get(sessionParams.mUid);
+
                 String predictedUrl = sessionParams.getPredictedUrl();
                 outcome = predictedUrl == null ? NO_PREDICTION
                         : predictedUrl.equals(url) ? GOOD_PREDICTION : BAD_PREDICTION;
@@ -408,6 +428,19 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
             RecordHistogram.recordCustomTimesHistogram("CustomTabs.PredictionToLaunch",
                     elapsedTimeMs, 1, TimeUnit.MINUTES.toMillis(3), TimeUnit.MILLISECONDS, 100);
         }
+        // CustomTabs.CalledWarmup histogram.
+        boolean warmupCalled = mWarmupHasBeenCalled.get();
+        int warmupKind = warmupCalled ? NO_SESSION_WARMUP : NO_SESSION_NO_WARMUP;
+        if (hasValidSession) {
+            if (hasUidCalledWarmup) {
+                warmupKind = SESSION_WARMUP;
+            } else {
+                warmupKind = warmupCalled ? SESSION_NO_WARMUP_ALREADY_CALLED
+                                          : SESSION_NO_WARMUP_NOT_CALLED;
+            }
+        }
+        RecordHistogram.recordEnumeratedHistogram(
+                "CustomTabs.CalledWarmup", warmupKind, SESSION_WARMUP_COUNT);
     }
 
     /**
@@ -637,6 +670,7 @@ public class CustomTabsConnection extends ICustomTabsService.Stub {
         SessionParams params = mSessionParams.get(session);
         if (params == null) return;
         mSessionParams.remove(session);
+        mUidHasCalledWarmup.delete(params.mUid);
         IBinder binder = params.mCallback.asBinder();
         binder.unlinkToDeath(params.mDeathRecipient, 0);
         if (mPrerender != null && session.equals(mPrerender.mSession)) {