Fix imcompatible app warning when insert to DayDream headset

chrome/android/java/AndroidManifest.xml

Index: chrome/android/java/AndroidManifest.xml
diff --git a/chrome/android/java/AndroidManifest.xml b/chrome/android/java/AndroidManifest.xml
index f8bdbdff185919cd08a8bd7e7dd5f10f18ef05ee..52170609e4841d228b24d8f0776cbe5d674fa542 100644
--- a/chrome/android/java/AndroidManifest.xml
+++ b/chrome/android/java/AndroidManifest.xml
@@ -353,6 +353,15 @@ by a child template that "extends" this file.
              android:launchMode="singleTask"
              android:configChanges="orientation|keyboardHidden|keyboard|screenSize|mcc|mnc|screenLayout|smallestScreenSize"
              android:hardwareAccelerated="false">
+            {% set enable_webvr = enable_webvr|default(0) %}
+            {% if enable_vr_shell == "true" or enable_webvr == "true" %}
+            <intent-filter>
+                <!-- Add a dummy action to match intent without any action. -->
+                <action android:name="org.chromium.chrome.browser.dummy.action" />

[Maria, 2016/10/26 20:10:27]

Why does a dummy name allow to match intent without any action?  Why wouldn't
there be an action on the intent?

[bshe, 2016/10/26 20:51:46]

Based on this doc:
https://developer.android.com/guide/components/intents-filters.html#ActionTest
It sounds like in order to pass action test for intent with no action, we need
to have a dummy action here.
 
The way Daydream figure out which category an activity belongs to is to test if
a Daydream category intent can be resolved.
And they didn't add any action when create the intent.

+                <category android:name="com.google.intent.category.DAYDREAM" />

[Maria, 2016/10/26 20:10:27]

Not too familiar with this -- I have a few questions:

1) Wouldn't this put this activity into Daydream launcher? The comment on
ChromeLauncherActivity seems to imply that's a side effect of adding the filter.

2) I imagine only ChromeLauncherActivity and Chrome internally sends intents
against ChromeTabbedActivity, so it's kind of weird that we have an intent
filter here.

[mthiesse, 2016/10/26 20:15:21]

I actually just had a discussion with Biao, and we don't want to be in the
Daydream launcher at all just yet (the cold launch experience is brutal).

Is there any way to fix the incompatible warning without being on the launcher?

[bshe, 2016/10/26 20:51:46]

This won't make Chrome appear in the launcher. To appear in launcher, it
requires
<action android:name="android.intent.action.MAIN" /> in addition to category.

[bshe, 2016/10/26 20:51:46]

So Daydream will try to test if their intents can be resolved by the foreground
activity.
And based on the result, it categorize the activity to Cardboard only, hybrid or
Daydream only.
ChromeLauncherActivity is a transit activity. So I have to add intent filter
here since this
is the activity that actually use Daydream api.

[Maria, 2016/10/26 21:07:24]

Ok, can you add this as a comment here -- I think people reading this later may
find it very surprising that there's an intent filter on a non-exported
activity.

[bshe, 2016/10/27 15:01:15]

Done.

+                <category android:name="com.google.intent.category.CARDBOARD" />
+            </intent-filter>
+            {% endif %}
         </activity>
         <activity android:name="org.chromium.chrome.browser.ChromeTabbedActivity2"
              android:theme="@style/TabbedModeTheme"