Implement the new Photo picker, part one.

ui/android/java/src/org/chromium/ui/UiUtils.java

Index: ui/android/java/src/org/chromium/ui/UiUtils.java
diff --git a/ui/android/java/src/org/chromium/ui/UiUtils.java b/ui/android/java/src/org/chromium/ui/UiUtils.java
index 61fa37f2cf3329ee49812dae8339a9d63282d62e..c0948beb0c97a77f2c26e5ac15ac586738afbaea 100644
--- a/ui/android/java/src/org/chromium/ui/UiUtils.java
+++ b/ui/android/java/src/org/chromium/ui/UiUtils.java
@@ -56,6 +56,9 @@ public class UiUtils {
     /** A delegate that allows disabling keyboard visibility detection. */
     private static KeyboardShowingDelegate sKeyboardShowingDelegate;
 
+    /** A delegate that shows the file picker. */

[Michael van Ouwerkerk, 2017/03/13 14:04:17]

It does more than showing the picker, so let's give it a more general doc: A
delegate for the tile picker.

[Finnur, 2017/03/14 14:35:41]

Done.

+    private static FilePickerDelegate sFilePickerDelegate;
+
     /**
      * A delegate that can be implemented to override whether or not keyboard detection will be
      * used.
@@ -71,6 +74,24 @@ public class UiUtils {
     }
 
     /**
+     * A delegate interface for showing the photo picker.
+     */
+    public interface FilePickerDelegate {

[Michael van Ouwerkerk, 2017/03/13 14:04:17]

This is called FilePicker but lots of places say photo picker. Could you make
these consistent?

[Finnur, 2017/03/14 14:35:41]

Done.

+        /**
+         * Called to display the photo picker.
+         * @param context  The context to use.
+         * @param listener The listener that will be notified of the selection.
+         * @param allowMultiple Whether the dialog should allow multiple images to be selected.
+         */
+        void showFilePicker(Context context, OnPhotoPickerListener listener, boolean allowMultiple);
+
+        /**
+         * Called when the photo picker dialog should be dismissed.
+         */
+        void dismissFilePicker();
+    }
+
+    /**
      * Allows setting a delegate to override the default software keyboard visibility detection.
      * @param delegate A {@link KeyboardShowingDelegate} instance.
      */
@@ -79,6 +100,14 @@ public class UiUtils {
     }
 
     /**
+     * Allows setting a delegate to override the default software keyboard visibility detection.

[Michael van Ouwerkerk, 2017/03/13 14:04:17]

These docs seem to have been copied from the method above.

[Finnur, 2017/03/14 14:35:41]

Yeah, special two-for one price at the store. Couldn't resit.

Fixed.

+     * @ param delegate A {@link KeyboardShowingDelegate} instance.
+     */
+    public static void setFilePickerDelegate(FilePickerDelegate delegate) {
+        sFilePickerDelegate = delegate;
+    }
+
+    /**
      * Shows the software keyboard if necessary.
      * @param view The currently focused {@link View}, which would receive soft keyboard input.
      */
@@ -170,6 +199,20 @@ public class UiUtils {
         return locales;
     }
 
+    // FilePickerDelegate:
+
+    public static boolean showFilePicker(
+            Context context, OnPhotoPickerListener listener, boolean allowMultiple) {
+        if (sFilePickerDelegate == null) return false;
+        sFilePickerDelegate.showFilePicker(context, listener, allowMultiple);
+        return true;
+    }
+
+    public static void dismissFilePicker() {
+        if (sFilePickerDelegate == null) return;
+        sFilePickerDelegate.dismissFilePicker();
+    }
+
     /**
      * Inserts a {@link View} into a {@link ViewGroup} after directly before a given {@View}.
      * @param container The {@link View} to add newView to.