[Location Suggestion] Update suggested spinner option.

This CL choose the suggested directory option based on available storage space.Test CL will be added later

Bug: 1118207
Change-Id: I70c71a8bba8677a57f2ed871d246a8b59f3c0783
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2406853
Commit-Queue: Hung Vu <vuhung@google.com>
Reviewed-by: Min Qin <qinmin@chromium.org>
Reviewed-by: Xing Liu <xingliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807212}

chrome/browser/download/android/java/src/org/chromium/chrome/browser/download/dialogs/DownloadLocationCustomView.java

@@ -42,6 +42,7 @@ public class DownloadLocationCustomView
     private Spinner mFileLocation;
     private CheckBox mDontShowAgain;
     private @DownloadLocationDialogType int mDialogType;
+    private long mTotalBytes;
 
     public DownloadLocationCustomView(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -71,6 +72,8 @@ public class DownloadLocationCustomView
 
         mFileName.setText(suggestedPath.getName());
         mTitle.setText(title);
+        mTotalBytes = totalBytes;
+
         switch (dialogType) {
             case DownloadLocationDialogType.DEFAULT:
                 // Show a file size subtitle if file size is available.
@@ -156,6 +159,9 @@ public class DownloadLocationCustomView
                 || mDialogType == DownloadLocationDialogType.LOCATION_NOT_FOUND) {
             selectedItemId = mDirectoryAdapter.useFirstValidSelectableItemId();
         }
+        if (mDialogType == DownloadLocationDialogType.LOCATION_SUGGESTION) {
+            selectedItemId = mDirectoryAdapter.useSuggestedItemId(mTotalBytes);
+        }
 
         mFileLocation.setAdapter(mDirectoryAdapter);
         mFileLocation.setSelection(selectedItemId);

chrome/browser/download/android/java/src/org/chromium/chrome/browser/download/settings/DownloadDirectoryAdapter.java

@@ -204,6 +204,41 @@ public class DownloadDirectoryAdapter extends ArrayAdapter<Object> {
         return 0;
     }
 
+    /**
+     * Get the ID of the suggested item based on total bytes and threshold.
+     * @param totalBytes The total bytes of the download file.
+     * @return  ID of the suggested item and the new default location.
+     */
+    public int useSuggestedItemId(long totalBytes) {
+        double maxSpaceLeft = 0;
+        int suggestedId = NO_SELECTED_ITEM_ID;
+        String defaultLocation = DownloadDialogBridge.getDownloadDefaultDirectory();
+
+        for (int i = 0; i < getCount(); i++) {
+            DirectoryOption option = (DirectoryOption) getItem(i);
+            if (option == null) continue;
+            if (defaultLocation.equals(option.location)) continue;
+
+            double spaceLeft = (double) (option.availableSpace - totalBytes) / option.totalSpace;
+            // If a larger storage is found, mark it as the suggested option.
+            if (spaceLeft > maxSpaceLeft) {
+                maxSpaceLeft = spaceLeft;
+                suggestedId = i;
+            }
+        }
+
+        // If there is a suggested option, set it as default directory and return its position.
+        if (suggestedId != NO_SELECTED_ITEM_ID) {
+            DirectoryOption suggestedOption = (DirectoryOption) getItem(suggestedId);
+            mSelectedPosition = suggestedId;
+            return suggestedId;
+        }
+
+        // Display an option that says there are no available download locations.
+        adjustErrorDirectoryOption();
+        return 0;
+    }
+
     boolean hasAvailableLocations() {
         return mErrorOptions.isEmpty();
     }