Custom Tabs: add speculation status histograms.

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 0e71b3ea77e622d1756d6bca214cac7c0d676f32..8aef37b28778455714586f6bcfd3d5a1c3df93bf 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
@@ -80,6 +80,30 @@ public class CustomTabsConnection {
     @VisibleForTesting
     static final String PAGE_LOAD_METRICS_CALLBACK = "NavigationMetrics";
 
+    // For CustomTabs.SpeculationStatusOnStart, see tools/metrics/enums.xml. Append only.
+    private static final int SPECULATION_STATUS_ON_START_ALLOWED = 0;
+    // What kind of speculation was started, counted in addition to
+    // SPECULATION_STATUS_ALLOWED.
+    private static final int SPECULATION_STATUS_ON_START_PREFETCH = 1;
+    private static final int SPECULATION_STATUS_ON_START_PRERENDER = 2;
+    private static final int SPECULATION_STATUS_ON_START_PRERENDER_NOT_STARTED = 3;
+    private static final int SPECULATION_STATUS_ON_START_BACKGROUND_TAB = 4;

[pasko, 2017/05/16 14:35:50]

nit: can we swap the order of PRERENDER_NOT_STARTED and BACKGROUND_TAB? The
latter starts a prerender and the former is close to the meaning of the aborted
series (though we do not have the visibility into why it was aborted"

[mattcary, 2017/05/22 10:07:11]

Sure, although personally I find it confusing to have the prerender statuses
spread around.

+    // The following describe reasons why a speculation was aborted at some point, and are
+    // counted instead of SPECULATION_STATUS_ALLOWED.
+    private static final int SPECULATION_STATUS_ON_START_ABORTED_DEVICE_CLASS = 5;
+    private static final int SPECULATION_STATUS_ON_START_ABORTED_BLOCK_3RD_PARTY_COOKIES = 6;
+    private static final int SPECULATION_STATUS_ON_START_ABORTED_NETWORK_PREDICTION_DISABLED = 7;
+    private static final int SPECULATION_STATUS_ON_START_ABORTED_DATA_REDUCTION_ENABLED = 8;
+    private static final int SPECULATION_STATUS_ON_START_ABORTED_NETWORK_METERED = 9;
+    private static final int SPECULATION_STATUS_ON_START_MAX = 10;
+
+    // For CustomTabs.SpeculationStatusOnSwap, see tools/metrics/enums.xml. Append only.
+    private static final int SPECULATION_STATUS_ON_SWAP_BACKGROUND_TAB_TAKEN = 0;
+    private static final int SPECULATION_STATUS_ON_SWAP_BACKGROUND_TAB_NOT_MATCHED = 1;
+    private static final int SPECULATION_STATUS_ON_SWAP_PRERENDER_TAKEN = 2;
+    private static final int SPECULATION_STATUS_ON_SWAP_PRERENDER_NOT_MATCHED = 3;
+    private static final int SPECULATION_STATUS_ON_SWAP_MAX = 4;
+
     // For testing only, DO NOT USE.
     @VisibleForTesting
     static final String DEBUG_OVERRIDE_KEY =
@@ -616,9 +640,11 @@ public class CustomTabsConnection {
                         && UrlUtilities.urlsMatchIgnoringFragments(prerenderedUrl, url));
         WebContents result = null;
         if (urlsMatch && TextUtils.equals(prerenderReferrer, referrer)) {
+            recordSpeculationStatusOnSwap(SPECULATION_STATUS_ON_SWAP_PRERENDER_TAKEN);
             result = webContents;
             mSpeculation = null;
         } else {
+            recordSpeculationStatusOnSwap(SPECULATION_STATUS_ON_SWAP_PRERENDER_NOT_MATCHED);
             cancelSpeculation(session);
         }
         if (!mClientManager.usesDefaultSessionParameters(session) && webContents != null) {
@@ -671,8 +697,11 @@ public class CustomTabsConnection {
                                    && UrlUtilities.urlsMatchIgnoringFragments(speculatedUrl, url));
                 if (referrer == null) referrer = "";
                 if (urlsMatch && TextUtils.equals(speculationReferrer, referrer)) {
+                    recordSpeculationStatusOnSwap(SPECULATION_STATUS_ON_SWAP_BACKGROUND_TAB_TAKEN);
                     return tab;
                 } else {
+                    recordSpeculationStatusOnSwap(
+                            SPECULATION_STATUS_ON_SWAP_BACKGROUND_TAB_NOT_MATCHED);
                     tab.destroy();
                 }
             }
@@ -953,19 +982,36 @@ public class CustomTabsConnection {
     }
 
     @VisibleForTesting
-    boolean maySpeculate(CustomTabsSessionToken session) {
-        if (!DeviceClassManager.enablePrerendering()) return false;
+    int maySpeculateWithResult(CustomTabsSessionToken session) {
+        if (!DeviceClassManager.enablePrerendering()) {
+            return SPECULATION_STATUS_ON_START_ABORTED_DEVICE_CLASS;
+        }
         PrefServiceBridge prefs = PrefServiceBridge.getInstance();
-        if (prefs.isBlockThirdPartyCookiesEnabled()) return false;
-        // TODO(yusufo): The check for prerender in PrivacyManager now checks for the network
-        // connection type as well, we should either change that or add another check for custom
-        // tabs. Then PrivacyManager should be used to make the below check.
-        if (!prefs.getNetworkPredictionEnabled()) return false;
-        if (DataReductionProxySettings.getInstance().isDataReductionProxyEnabled()) return false;
+        if (prefs.isBlockThirdPartyCookiesEnabled()) {
+            return SPECULATION_STATUS_ON_START_ABORTED_BLOCK_3RD_PARTY_COOKIES;
+        }
+        // TODO(yusufo): The check for prerender in PrivacyPreferencesManager now checks for the
+        // network connection type as well, we should either change that or add another check for
+        // custom tabs. Then PrivacyManager should be used to make the below check.
+        if (!prefs.getNetworkPredictionEnabled()) {
+            return SPECULATION_STATUS_ON_START_ABORTED_NETWORK_PREDICTION_DISABLED;
+        }
+        if (DataReductionProxySettings.getInstance().isDataReductionProxyEnabled()) {
+            return SPECULATION_STATUS_ON_START_ABORTED_DATA_REDUCTION_ENABLED;
+        }
         ConnectivityManager cm =
                 (ConnectivityManager) mApplication.getApplicationContext().getSystemService(
                         Context.CONNECTIVITY_SERVICE);
-        return !cm.isActiveNetworkMetered() || shouldPrerenderOnCellularForSession(session);
+        if (cm.isActiveNetworkMetered() && !shouldPrerenderOnCellularForSession(session)) {
+            return SPECULATION_STATUS_ON_START_ABORTED_NETWORK_METERED;
+        }
+        return SPECULATION_STATUS_ON_START_ALLOWED;
+    }
+
+    boolean maySpeculate(CustomTabsSessionToken session) {
+        int speculationResult = maySpeculateWithResult(session);
+        recordSpeculationStatusOnStart(speculationResult);
+        return speculationResult == SPECULATION_STATUS_ON_START_ALLOWED;
     }
 
     /** Cancels the speculation for a given session, or any session if null. */
@@ -1005,15 +1051,20 @@ public class CustomTabsConnection {
         }
         switch (speculationMode) {
             case SpeculationParams.PREFETCH:
+                recordSpeculationStatusOnStart(SPECULATION_STATUS_ON_START_PREFETCH);
                 boolean didPrefetch = new ResourcePrefetchPredictor(profile).startPrefetching(url);
                 if (didPrefetch) mSpeculation = SpeculationParams.forPrefetch(session, url);
                 preconnect = !didPrefetch;
                 break;
             case SpeculationParams.PRERENDER:
                 boolean didPrerender = prerenderUrl(session, url, extras, uid);
+                recordSpeculationStatusOnStart(didPrerender
+                                ? SPECULATION_STATUS_ON_START_PRERENDER
+                                : SPECULATION_STATUS_ON_START_PRERENDER_NOT_STARTED);
                 createSpareWebContents = !didPrerender;
                 break;
             case SpeculationParams.HIDDEN_TAB:
+                recordSpeculationStatusOnStart(SPECULATION_STATUS_ON_START_BACKGROUND_TAB);
                 launchUrlInHiddenTab(session, url, extras);
                 break;
             default:
@@ -1145,4 +1196,14 @@ public class CustomTabsConnection {
         if (referrer == null) referrer = "";
         return referrer;
     }
+
+    private void recordSpeculationStatusOnStart(int status) {
+        RecordHistogram.recordEnumeratedHistogram(
+                "CustomTabs.SpeculationStatusOnStart", status, SPECULATION_STATUS_ON_START_MAX);
+    }
+
+    private void recordSpeculationStatusOnSwap(int status) {
+        RecordHistogram.recordEnumeratedHistogram(
+                "CustomTabs.SpeculationStatusOnSwap", status, SPECULATION_STATUS_ON_SWAP_MAX);
+    }
 }