SkyDemo should launch demos in their own windows

R=eseidel@chromium.org, eseidel@google.com

Review URL: https://codereview.chromium.org/1214633008 .

sdk/example/demo_launcher/apk/AndroidManifest.xml

@@ -10,7 +10,12 @@
     <uses-feature android:name="android.hardware.sensor.accelerometer" android:required="true" />
 
     <application android:icon="@mipmap/ic_launcher" android:label="Sky" android:name="SkyDemoApplication">
-        <activity android:configChanges="orientation|keyboardHidden|keyboard|screenSize" android:hardwareAccelerated="true" android:name="SkyDemoActivity" android:theme="@android:style/Theme.Holo.Light.NoActionBar">
+        <activity android:name="SkyDemoActivity"
+                  android:launchMode="standard"
+                  android:documentLaunchMode="always"
+                  android:hardwareAccelerated="true"
+                  android:configChanges="orientation|keyboardHidden|keyboard|screenSize"
+                  android:theme="@android:style/Theme.Holo.Light.NoActionBar">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />

sdk/example/demo_launcher/lib/main.dart

@@ -5,6 +5,7 @@
 import 'dart:sky';
 
 import 'package:mojom/intents/intents.mojom.dart';
+import 'package:sky/mojo/activity.dart' as activity;
 import 'package:sky/mojo/asset_bundle.dart';
 import 'package:sky/mojo/shell.dart' as shell;
 import 'package:sky/painting/box_painter.dart';
@@ -38,6 +39,7 @@ void launch(String relativeUrl, String bundle) {
   Intent intent = new Intent()
     ..action = 'android.intent.action.VIEW'
     ..component = component
+    ..flags = activity.MULTIPLE_TASK | activity.NEW_DOCUMENT
     ..url = url.toString();
 
   if (bundle != null) {
@@ -47,8 +49,7 @@ void launch(String relativeUrl, String bundle) {
     intent.stringExtras = [extra];
   }
 
-  shell.requestService(null, activityManager);
-  activityManager.ptr.startActivity(intent);
+  activity.startActivity(intent);
 }
 
 class SkyDemo {

sdk/lib/mojo/activity.dart

@@ -5,8 +5,22 @@
 import 'package:mojom/intents/intents.mojom.dart';
 import 'package:sky/mojo/shell.dart' as shell;
 
+const int NEW_DOCUMENT = 0x00080000;
+const int NEW_TASK = 0x10000000;
+const int MULTIPLE_TASK = 0x08000000;
+
+ActivityManagerProxy _initActivityManager() {
+  ActivityManagerProxy activityManager = new ActivityManagerProxy.unbound();
+  shell.requestService('mojo:sky_viewer', activityManager);
+  return activityManager;
+}
+
+final ActivityManagerProxy _activityManager = _initActivityManager();
+
 void finishCurrentActivity() {
-    ActivityManagerProxy activityManager = new ActivityManagerProxy.unbound();
-    shell.requestService('mojo:sky_viewer', activityManager);
-    activityManager.ptr.finishCurrentActivity();
-}
\ No newline at end of file
+  _activityManager.ptr.finishCurrentActivity();
+}
+
+void startActivity(Intent intent) {
+  _activityManager.ptr.startActivity(intent);
+}

services/intents/intents.mojom

@@ -17,6 +17,7 @@ struct ComponentName {
 struct Intent {
   string action;
   string url;
+  uint32 flags;
   ComponentName? component;
   array<StringExtra>? string_extras;
 };

services/intents/src/org/domokit/intents/ActivityManagerImpl.java

@@ -40,6 +40,11 @@ public class ActivityManagerImpl implements ActivityManager {
 
     @Override
     public void startActivity(Intent intent) {
+        if (sCurrentActivity == null) {
+            Log.e(TAG, "Unable to startActivity");
+            return;
+        }
+
         final android.content.Intent androidIntent = new android.content.Intent(
                 intent.action, Uri.parse(intent.url));
 
@@ -56,10 +61,12 @@ public class ActivityManagerImpl implements ActivityManager {
             }
         }
 
-        androidIntent.addFlags(android.content.Intent.FLAG_ACTIVITY_NEW_TASK);
+        if (intent.flags != 0) {
+            androidIntent.setFlags(intent.flags);
+        }
 
         try {
-            mContext.startActivity(androidIntent);
+            sCurrentActivity.startActivity(androidIntent);
         } catch (ActivityNotFoundException e) {
             Log.e(TAG, "Unable to startActivity", e);
         }