Propagate error messages to UI for blimp.

chrome/android/java/src/org/chromium/chrome/browser/blimp/ui/BlimpMessageBuilder.java

Index: chrome/android/java/src/org/chromium/chrome/browser/blimp/ui/BlimpMessageBuilder.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/blimp/ui/BlimpMessageBuilder.java b/chrome/android/java/src/org/chromium/chrome/browser/blimp/ui/BlimpMessageBuilder.java
new file mode 100644
index 0000000000000000000000000000000000000000..0b78033d3eed578ceb55e3013eb49c1774c65b98
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/blimp/ui/BlimpMessageBuilder.java
@@ -0,0 +1,90 @@
+// Copyright 2016 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.blimp.ui;
+
+import android.app.Activity;
+
+import org.chromium.base.ApplicationStatus;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.chrome.browser.snackbar.Snackbar;
+import org.chromium.chrome.browser.snackbar.SnackbarManager;
+import org.chromium.chrome.browser.snackbar.SnackbarManager.SnackbarController;
+import org.chromium.ui.widget.Toast;
+
+/**
+ * BlimpMessageBuilder is a helper class to show message in a {@link Snackbar} or Toast.
+ */
+public class BlimpMessageBuilder implements SnackbarController {
+    public enum MessageLength {
+        SHORT,
+        LONG,
+    }
+
+    private static final int BLIMP_SNACKBAR_DURATION_LONG_MS = 6000;
+    private static final int BLIMP_SNACKBAR_DURATION_SHORT_MS = 3000;
+
+    private Snackbar mSnackbar;
+    private MessageLength mLength = MessageLength.LONG;
+
+    /**
+     * Show a message in a {@link Snackbar} or {@link Toast}.
+     * If the current foreground activity doesn't have a {@link SnackbarManager}, fall back to
+     * show a Toast.
+     * @param message Message to show.
+     */
+    public void showMessage(String message) {
+        mSnackbar = null;
+        Activity activity = ApplicationStatus.getLastTrackedFocusedActivity();
+        SnackbarManager manager = getSnackbarManager(activity);
+
+        // Fall back to show Toast if no SnackbarManager is found in the foreground activity.
+        if (manager == null) {
+            int length = (mLength == MessageLength.SHORT ? Toast.LENGTH_SHORT : Toast.LENGTH_LONG);
+            Toast.makeText(activity, message, length).show();
+            return;
+        }
+
+        // Show a Snackbar message.
+        int length = (mLength == MessageLength.SHORT ? BLIMP_SNACKBAR_DURATION_SHORT_MS
+                                                     : BLIMP_SNACKBAR_DURATION_LONG_MS);
+        mSnackbar = Snackbar.make(message, this, Snackbar.TYPE_NOTIFICATION, Snackbar.UMA_BLIMP)
+                            .setSingleLine(false)
+                            .setDuration(length);
+        manager.showSnackbar(mSnackbar);
+    }
+
+    /**
+     * Set the message duration.
+     * @param length Message length defined in {@link MessageLength}.
+     * @return The message builder.
+     */
+    public BlimpMessageBuilder setDuration(MessageLength length) {
+        mLength = length;
+        return this;
+    }
+
+    @Override
+    public void onAction(Object actionData) {}
+
+    @Override
+    public void onDismissNoAction(Object actionData) {}
+
+    /**
+     * Get {@link SnackbarManager} of current focused activity.
+     * @return The SnackbarManager or null if the activity doesn't hold a SnackbarManager.
+     */
+    @VisibleForTesting
+    protected SnackbarManager getSnackbarManager(Activity activity) {
+        if (activity != null && activity instanceof SnackbarManager.SnackbarManageable) {
+            return ((SnackbarManager.SnackbarManageable) activity).getSnackbarManager();
+        }
+        return null;
+    }
+
+    @VisibleForTesting
+    protected Snackbar getSnackbarForTest() {
+        return mSnackbar;
+    }
+}