Upstream Chrome for Android Cast.

chrome/android/java/src/org/chromium/chrome/browser/media/remote/FullscreenMediaRouteButton.java

Index: chrome/android/java/src/org/chromium/chrome/browser/media/remote/FullscreenMediaRouteButton.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/media/remote/FullscreenMediaRouteButton.java b/chrome/android/java/src/org/chromium/chrome/browser/media/remote/FullscreenMediaRouteButton.java
new file mode 100644
index 0000000000000000000000000000000000000000..99194f6966038701ab1546a199cd5543fd76742d
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/media/remote/FullscreenMediaRouteButton.java
@@ -0,0 +1,70 @@
+// Copyright 2012 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.media.remote;
+
+import android.content.Context;
+import android.support.v7.app.MediaRouteButton;
+import android.util.AttributeSet;
+import android.view.View;
+
+/**
+ * Cast button that wraps around a MediaRouteButton. We show the button only if there are available
+ * cast devices.
+ */
+public class FullscreenMediaRouteButton extends MediaRouteButton {
+
+    // Are we in the time window when the button should become visible if there're routes?
+    private boolean mVisibilityRequested;
+
+    /**
+     * The constructor invoked when inflating the button.
+     */
+    public FullscreenMediaRouteButton(Context context, AttributeSet attributeSet) {
+        super(context, attributeSet);
+        mVisibilityRequested = false;
+    }
+
+    /**
+     * Set the necessary state for the button to work.
+     */
+    public void initialize(MediaRouteController controller) {
+        setRouteSelector(controller.buildMediaRouteSelector());
+        setDialogFactory(new ChromeMediaRouteDialogFactory());
+    }
+
+    @Override
+    public void setEnabled(boolean enabled) {
+        if (!RemoteMediaPlayerController.isRemotePlaybackEnabled()) return;
+
+        // We need to check if the button was in the same state before to avoid doing anything,
+        // but we also need to update the current state for {@link #setButtonVisibility} to work.
+        boolean wasEnabled = isEnabled();
+        super.setEnabled(enabled);
+
+        if (wasEnabled == enabled) return;

[qinmin, 2015/03/20 19:35:46]

can this line be moved on top of the super.setEnabled(enabled)?

[aberent, 2015/03/23 17:35:31]

No idea. There seems to have been a history of subtle changes to this code
downstream (e.g. moving where the super.setEnabled is done) without adequate
documentation. As such, I would, for now, prefer to leave this alone, and do
some experiments later, leading possibly to an additional CL.

Added a TODO.

[whywhat, 2015/03/23 17:46:35]

Actually, setButtonVisibility() below depends on isEnabled() state so it has to
be updated before setButtonVisibility() is called. We could pass enabled there
though (in a follow up CL).

+
+        if (enabled && mVisibilityRequested) {
+            setButtonVisibility(View.VISIBLE);
+        } else {
+            setVisibility(View.GONE);
+        }
+    }
+
+    private void setButtonVisibility(int visibility) {
+        // If the button is being set to visible, first make sure that it can even cast
+        // to anything before making it actually visible.
+        if (visibility == View.VISIBLE) {
+            if (isEnabled()) {
+                setVisibility(View.VISIBLE);
+            } else {
+                setVisibility(View.GONE);
+            }
+        } else {
+            setVisibility(visibility);
+        }
+    }
+
+}
+