Add UMA for studying download cancellation reasons

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 a64324b2dc9c25e865e50c3654be8af0c3404620..f12405b1d867bd4e086d7da98f4d700d7da64206 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
@@ -1129,12 +1129,14 @@ public class DownloadManagerService extends BroadcastReceiver implements
     /**
      * Called to cancel a download.
      * @param downloadGuid GUID of the download.
+     * @param isNotificationDismissed Whether cancel is caused by dismissing the notification.
      */
-    void cancelDownload(String downloadGuid) {
+    void cancelDownload(String downloadGuid, boolean isNotificationDismissed) {
         DownloadProgress progress = mDownloadProgressMap.get(downloadGuid);
         boolean isOffTheRecord = progress == null
                 ? false : progress.mDownloadItem.getDownloadInfo().isOffTheRecord();
-        nativeCancelDownload(getNativeDownloadManagerService(), downloadGuid, isOffTheRecord);
+        nativeCancelDownload(getNativeDownloadManagerService(), downloadGuid, isOffTheRecord,
+                isNotificationDismissed);
         recordDownloadFinishedUMA(DOWNLOAD_STATUS_CANCELLED, downloadGuid, 0);
     }
 
@@ -1468,6 +1470,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
     private native void nativeResumeDownload(
             long nativeDownloadManagerService, String downloadGuid);
     private native void nativeCancelDownload(
-            long nativeDownloadManagerService, String downloadGuid, boolean isOffTheRecord);
+            long nativeDownloadManagerService, String downloadGuid, boolean isOffTheRecord,
+            boolean isNotificationDismissed);
     private native void nativePauseDownload(long nativeDownloadManagerService, String downloadGuid);
 }