Photo Picker dialog: Add UMA statistics.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.java

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.photo_picker;
 
 import android.app.Activity;
 import android.content.Context;
 import android.content.DialogInterface;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
 import android.graphics.Rect;
 import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.LruCache;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.Button;
 import android.widget.RelativeLayout;
 
 import org.chromium.base.VisibleForTesting;
+import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.widget.selection.SelectableListLayout;
 import org.chromium.chrome.browser.widget.selection.SelectionDelegate;
 import org.chromium.ui.PhotoPickerListener;
 
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
 /**
  * A class for keeping track of common data associated with showing photos in
  * the photo picker, for example the RecyclerView and the bitmap caches.
  */
 public class PickerCategoryView extends RelativeLayout
         implements FileEnumWorkerTask.FilesEnumeratedCallback, RecyclerView.RecyclerListener,
                    DecoderServiceHost.ServiceReadyCallback, View.OnClickListener {
     private static final int KILOBYTE = 1024;
 
+    // The UMA key for tracking the actions taken in the dialog.
+    private static final String HISTOGRAM_NAME = "Android.PhotoPicker.DialogAction";

[Theresa, 2017/05/31 18:40:02]

optional nit: The downside to using a static final String is that our presubmit
scripts can't check for missing histograms. Typically we just duplicate the
string in-line in the calls to record histograms so that the presubmit checks
work.

[Finnur, 2017/06/01 15:13:55]

Done.

+
+    // Note: these values must match the PhotoPickerDialogAction enum values in histograms.xml.
+    // Only add new values at the end, right before ACTIONS. We depend on these specific values in
+    // UMA histograms.
+    private static final int ACTION_CANCEL = 0;
+    private static final int ACTION_PHOTO_PICKED = 1;
+    private static final int ACTION_NEW_PHOTO = 2;
+    private static final int ACTION_BROWSE = 3;
+    private static final int NUM_ACTIONS = 4;

[Theresa, 2017/05/31 18:40:02]

nit: ACTIONS_BOUNDARY is more consistent with how we usually specify histogram
enum boundaries.

[Finnur, 2017/06/01 15:13:55]

Done.

+
     // The dialog that owns us.
     private PhotoPickerDialog mDialog;
 
     // The view containing the RecyclerView and the toolbar, etc.
     private SelectableListLayout<PickerBitmap> mSelectableListLayout;
 
     // Our context.
     private Context mContext;
 
     // The list of images on disk, sorted by last-modified first.
@@ skipping 138 matching lines @@
             PhotoPickerDialog dialog, PhotoPickerListener listener, boolean multiSelectionAllowed) {
         if (!multiSelectionAllowed) mSelectionDelegate.setSingleSelectionMode();
 
         mDialog = dialog;
         mMultiSelectionAllowed = multiSelectionAllowed;
         mListener = listener;
 
         mDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
             @Override
             public void onCancel(DialogInterface dialog) {
+                RecordHistogram.recordEnumeratedHistogram(
+                        HISTOGRAM_NAME, ACTION_CANCEL, NUM_ACTIONS);
                 mListener.onPickerUserAction(PhotoPickerListener.Action.CANCEL, null);
             }
         });
     }
 
     // FileEnumWorkerTask.FilesEnumeratedCallback:
 
     @Override
     public void filesEnumeratedCallback(List<PickerBitmap> files) {
         mPickerBitmaps = files;
@@ skipping 17 matching lines @@
         if (filePath != null) {
             getDecoderServiceHost().cancelDecodeImage(filePath);
         }
     }
 
     // OnClickListener:
 
     @Override
     public void onClick(View view) {
         if (view.getId() == R.id.done) {
+            RecordHistogram.recordEnumeratedHistogram(
+                    HISTOGRAM_NAME, ACTION_PHOTO_PICKED, NUM_ACTIONS);
             notifyPhotosSelected();
         } else {
+            RecordHistogram.recordEnumeratedHistogram(HISTOGRAM_NAME, ACTION_CANCEL, NUM_ACTIONS);
             mListener.onPickerUserAction(PhotoPickerListener.Action.CANCEL, null);
         }
 
         mDialog.dismiss();
     }
 
     /**
      * Start loading of bitmaps, once files have been enumerated and service is
      * ready to decode.
      */
@@ skipping 30 matching lines @@
     }
 
     public boolean isMultiSelectAllowed() {
         return mMultiSelectionAllowed;
     }
 
     /**
      * Notifies the listener that the user selected to launch the gallery.
      */
     public void showGallery() {
+        RecordHistogram.recordEnumeratedHistogram(HISTOGRAM_NAME, ACTION_BROWSE, NUM_ACTIONS);
         mListener.onPickerUserAction(PhotoPickerListener.Action.LAUNCH_GALLERY, null);
     }
 
     /**
      * Notifies the listener that the user selected to launch the camera intent.
      */
     public void showCamera() {
+        RecordHistogram.recordEnumeratedHistogram(HISTOGRAM_NAME, ACTION_NEW_PHOTO, NUM_ACTIONS);
         mListener.onPickerUserAction(PhotoPickerListener.Action.LAUNCH_CAMERA, null);
     }
 
     /**
      * Calculates image size and how many columns can fit on-screen.
      */
     private void calculateGridMetrics() {
         Rect appRect = new Rect();
         ((Activity) mContext).getWindow().getDecorView().getWindowVisibleDisplayFrame(appRect);
 
@@ skipping 83 matching lines @@
     @VisibleForTesting
     public static void setTestFiles(List<PickerBitmap> testFiles) {
         sTestFiles = new ArrayList<>(testFiles);
     }
 
     @VisibleForTesting
     public SelectionDelegate<PickerBitmap> getSelectionDelegateForTesting() {
         return mSelectionDelegate;
     }
 }