Add new UMA to record the bytes wasted due to download resumption

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java

Index: chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
index d3449c20b7c0b7b26fc7006c092b7a7169235d57..3071fcf41e31fb4c09cfeaedfa72be9ff6271730 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
@@ -80,6 +80,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
     // Wait 10 seconds to resume all downloads, so that we won't impact tab loading.
     private static final long RESUME_DELAY_MILLIS = 10000;
     private static final int UNKNOWN_DOWNLOAD_STATUS = -1;
+    public static final long UNKNOWN_BYTES_RECEIVED = -1;
     private static final String PREF_IS_DOWNLOAD_HOME_ENABLED =
             "org.chromium.chrome.browser.download.IS_DOWNLOAD_HOME_ENABLED";
 
@@ -91,6 +92,8 @@ public class DownloadManagerService extends BroadcastReceiver implements
     private static final int UMA_DOWNLOAD_RESUMPTION_AUTO_STARTED = 4;
     private static final int UMA_DOWNLOAD_RESUMPTION_COUNT = 5;
 
+    private static final int GB_IN_KILO_BYTES = 1024 * 1024;
+
     // Set will be more expensive to initialize, so use an ArrayList here.
     private static final List<String> MIME_TYPES_TO_OPEN = new ArrayList<String>(Arrays.asList(
             OMADownloadHandler.OMA_DOWNLOAD_DESCRIPTOR_MIME,
@@ -723,6 +726,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
                 ? isSupportedMimeType(downloadItem.getDownloadInfo().getMimeType()) : false;
         String id = downloadItem.getId();
         DownloadProgress progress = mDownloadProgressMap.get(id);
+        long bytesReceived = downloadItem.getDownloadInfo().getBytesReceived();
         if (progress == null) {
             if (!downloadItem.getDownloadInfo().isPaused()) {
                 long startTime = System.currentTimeMillis();
@@ -731,9 +735,12 @@ public class DownloadManagerService extends BroadcastReceiver implements
                 progress.mIsUpdated = true;
                 progress.mIsSupportedMimeType = isSupportedMimeType;
                 mDownloadProgressMap.put(id, progress);
-                if (getUmaStatsEntry(downloadItem.getId()) == null) {
+                DownloadUmaStatsEntry entry = getUmaStatsEntry(downloadItem.getId());
+                if (entry == null) {
                     addUmaStatsEntry(new DownloadUmaStatsEntry(
-                            downloadItem.getId(), startTime, 0, false, false));
+                            downloadItem.getId(), startTime, 0, false, false, bytesReceived, 0));
+                } else if (updateBytesReceived(entry, bytesReceived)) {
+                    storeUmaEntries();
                 }
             }
             return;
@@ -755,11 +762,13 @@ public class DownloadManagerService extends BroadcastReceiver implements
             case DOWNLOAD_STATUS_INTERRUPTED:
                 entry = getUmaStatsEntry(downloadItem.getId());
                 entry.numInterruptions++;
+                updateBytesReceived(entry, bytesReceived);
                 storeUmaEntries();
                 break;
             case DOWNLOAD_STATUS_IN_PROGRESS:
                 entry = getUmaStatsEntry(downloadItem.getId());
-                if (entry.isPaused != downloadItem.getDownloadInfo().isPaused()) {
+                if (entry.isPaused != downloadItem.getDownloadInfo().isPaused()
+                        || updateBytesReceived(entry, bytesReceived)) {
                     entry.isPaused = downloadItem.getDownloadInfo().isPaused();
                     storeUmaEntries();
                 }
@@ -770,6 +779,22 @@ public class DownloadManagerService extends BroadcastReceiver implements
     }
 
     /**
+     * Helper method to update the received bytes and wasted bytes for UMA reporting.
+     * @param  entry UMA entry to update.
+     * @param bytesReceived The current received bytes.
+     * @return true if the UMA stats is updated, or false otherwise.
+     */
+    private boolean updateBytesReceived(DownloadUmaStatsEntry entry, long bytesReceived) {
+        if (bytesReceived == UNKNOWN_BYTES_RECEIVED || bytesReceived == entry.lastBytesReceived) {
+            return false;
+        }
+        if (bytesReceived < entry.lastBytesReceived) {
+            entry.bytesWasted += entry.lastBytesReceived - bytesReceived;
+        }
+        entry.lastBytesReceived = bytesReceived;
+        return true;
+    }
+    /**
      * Sets the download handler for OMA downloads, for testing purpose.
      *
      * @param omaDownloadHandler Download handler for OMA contents.
@@ -920,7 +945,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
                     mDownloadItem.getSystemDownloadId());
             if (!result) {
                 onDownloadFailed(mDownloadItem.getDownloadInfo().getFileName(), mFailureReason);
-                recordDownloadCompletionStats(true, DOWNLOAD_STATUS_FAILED, 0, 0, 0);
+                recordDownloadCompletionStats(true, DOWNLOAD_STATUS_FAILED, 0, 0, 0, 0);
                 if (isPendingOMADownload) {
                     mOMADownloadHandler.onDownloadFailed(
                             mDownloadItem.getDownloadInfo(), mDownloadItem.getSystemDownloadId(),
@@ -948,7 +973,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
                         new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
             }
             addUmaStatsEntry(new DownloadUmaStatsEntry(
-                    String.valueOf(mDownloadId), mStartTime, 0, false, true));
+                    String.valueOf(mDownloadId), mStartTime, 0, false, true, 0, 0));
             mDownloadItem.setSystemDownloadId(mDownloadId);
             mDownloadItem.setStartTime(mStartTime);
             mSystemDownloadIdMap.put(mDownloadId, mDownloadItem);
@@ -1171,7 +1196,8 @@ public class DownloadManagerService extends BroadcastReceiver implements
         if (progress != null && (progress.mDownloadStatus == DOWNLOAD_STATUS_INTERRUPTED
                 || progress.mDownloadStatus == DOWNLOAD_STATUS_IN_PROGRESS)) {
             DownloadInfo info = DownloadInfo.Builder.fromDownloadInfo(
-                    progress.mDownloadItem.getDownloadInfo()).setIsPaused(true).build();
+                    progress.mDownloadItem.getDownloadInfo()).setIsPaused(true)
+                    .setBytesReceived(UNKNOWN_BYTES_RECEIVED).build();
             onDownloadUpdated(info);
         }
     }
@@ -1278,7 +1304,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
      * @param numInterruptions Number of interruptions during the download.
      */
     private void recordDownloadCompletionStats(boolean useDownloadManager, int status,
-            long totalDuration, long bytesDownloaded, int numInterruptions) {
+            long totalDuration, long bytesDownloaded, int numInterruptions, long bytesWasted) {
         switch (status) {
             case DOWNLOAD_STATUS_COMPLETE:
                 if (useDownloadManager) {
@@ -1298,6 +1324,8 @@ public class DownloadManagerService extends BroadcastReceiver implements
                     RecordHistogram.recordCountHistogram(
                             "MobileDownload.InterruptionsCount.ChromeNetworkStack.Success",
                             numInterruptions);
+                    recordBytesWasted(
+                            "MobileDownload.BytesWasted.ChromeNetworkStack.Success", bytesWasted);
                 }
                 break;
             case DOWNLOAD_STATUS_FAILED:
@@ -1318,6 +1346,8 @@ public class DownloadManagerService extends BroadcastReceiver implements
                     RecordHistogram.recordCountHistogram(
                             "MobileDownload.InterruptionsCount.ChromeNetworkStack.Failure",
                             numInterruptions);
+                    recordBytesWasted(
+                            "MobileDownload.BytesWasted.ChromeNetworkStack.Failure", bytesWasted);
                 }
                 break;
             case DOWNLOAD_STATUS_CANCELLED:
@@ -1328,6 +1358,8 @@ public class DownloadManagerService extends BroadcastReceiver implements
                     RecordHistogram.recordCountHistogram(
                             "MobileDownload.InterruptionsCount.ChromeNetworkStack.Cancel",
                             numInterruptions);
+                    recordBytesWasted(
+                            "MobileDownload.BytesWasted.ChromeNetworkStack.Cancel", bytesWasted);
                 }
                 break;
             default:
@@ -1335,6 +1367,16 @@ public class DownloadManagerService extends BroadcastReceiver implements
         }
     }
 
+    /**
+     * Helper method to record the bytes wasted metrics when a download completes.
+     * @param name Histogram name
+     * @param bytesWasted Bytes wasted during download.
+     */
+    private void recordBytesWasted(String name, long bytesWasted) {
+        RecordHistogram.recordCustomCountHistogram(
+                name, (int) (bytesWasted / 1024), 1, GB_IN_KILO_BYTES, 50);
+    }
+
     @Override
     public void onQueryCompleted(
             DownloadManagerDelegate.DownloadQueryResult result, boolean showNotification) {
@@ -1361,7 +1403,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
             }
         }
         recordDownloadCompletionStats(true, result.downloadStatus,
-                result.downloadTimeInMilliseconds, result.bytesDownloaded, 0);
+                result.downloadTimeInMilliseconds, result.bytesDownloaded, 0, 0);
         removeUmaStatsEntry(result.item.getId());
     }
 
@@ -1525,7 +1567,8 @@ public class DownloadManagerService extends BroadcastReceiver implements
         long currentTime = System.currentTimeMillis();
         long totalTime = Math.max(0, currentTime - entry.downloadStartTime);
         recordDownloadCompletionStats(
-                false, downloadStatus, totalTime, bytesDownloaded, entry.numInterruptions);
+                false, downloadStatus, totalTime, bytesDownloaded, entry.numInterruptions,
+                entry.bytesWasted);
         removeUmaStatsEntry(entryId);
     }