[Android] Prompt with infobar on filename conflict

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

Index: chrome/android/java/src/org/chromium/chrome/browser/download/ChromeDownloadDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/ChromeDownloadDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/download/ChromeDownloadDelegate.java
index d03d98fb8ab7aff8fb84a599da3c6782847c23bc..9b182d3496b9acad17eae3740dff728447b3f113 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/download/ChromeDownloadDelegate.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/ChromeDownloadDelegate.java
@@ -22,6 +22,7 @@ import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.Tab;
 import org.chromium.chrome.browser.infobar.ConfirmInfoBar;
+import org.chromium.chrome.browser.infobar.DownloadOverwriteInfoBar;
 import org.chromium.chrome.browser.infobar.InfoBar;
 import org.chromium.chrome.browser.infobar.InfoBarListeners;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
@@ -306,12 +307,56 @@ public class ChromeDownloadDelegate
         confirmDangerousDownload(downloadInfo);
     }
 
+    private boolean launchInfoBarIfFileExists(final DownloadInfo info) {
+        String fileName = info.getFileName();
+        File dir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
+        if (!dir.mkdir() && !dir.isDirectory()) return false;
+        String dirName = dir.getName();
+        final File file = new File(dir, info.getFileName());
+        String fullDirPath = file.getParent();
+        if (!file.exists()) return false;
+        if (TextUtils.isEmpty(fileName) || TextUtils.isEmpty(dirName)
+                || TextUtils.isEmpty(fullDirPath)) {
+            return false;
+        }
+
+        InfoBar infoBar = new DownloadOverwriteInfoBar(0, new DownloadOverwriteInfoBar.Callback() {
+            @Override
+            public void onCloseButtonClicked(DownloadOverwriteInfoBar infoBar) {
+                infoBar.dismissJavaOnlyInfoBar();
+            }
+
+            @Override
+            public void onAction(DownloadOverwriteInfoBar infoBar, int action) {
+                if (action == InfoBar.ACTION_TYPE_OVERWRITE) {
+                    // Android DownloadManager does not have an overwriting option.
+                    // We remove the file here instead.
+                    file.delete();
+                }
+                if (action == InfoBar.ACTION_TYPE_OVERWRITE
+                        || action == InfoBar.ACTION_TYPE_CREATE_NEW_FILE) {
+                    enqueueDownloadManagerRequestInternal(info);
+                }
+                infoBar.dismissJavaOnlyInfoBar();
+            }
+        }, fileName, dirName, fullDirPath);
+        infoBar.setExpireOnNavigation(false);
+        mTab.getInfoBarContainer().addInfoBar(infoBar);
+        return true;
+    }
+
     /**
      * Sends the download request to Android download manager.
      *
      * @param info Download information about the download.
      */
     protected void enqueueDownloadManagerRequest(final DownloadInfo info) {
+        if (!launchInfoBarIfFileExists(info)) {
+            enqueueDownloadManagerRequestInternal(info);
+        }
+    }
+
+    private void enqueueDownloadManagerRequestInternal(final DownloadInfo info) {
         DownloadManagerService.getDownloadManagerService(
                 mContext.getApplicationContext()).enqueueDownloadManagerRequest(info, true);
         closeBlankTab();