Add <intent-filter> support to <provider>.

For the new documents work, we're only interested in the subset of
ContentProviders that actually implement DocumentsContract.  Instead
of returning all providers, add <intent-filter> support to make it
easier to limit the set of returned ProviderInfo.

Define a well-known action for DocumentsProviders, and start using it
when querying for roots.  Continue supporting the old <meta-data>
approach until all apps have been updated.

Bug: 8599233
Change-Id: I05f049bba21311f5421738002f99ee214447c909
diff --git a/packages/ExternalStorageProvider/AndroidManifest.xml b/packages/ExternalStorageProvider/AndroidManifest.xml
index 7094efc..99a4260 100644
--- a/packages/ExternalStorageProvider/AndroidManifest.xml
+++ b/packages/ExternalStorageProvider/AndroidManifest.xml
@@ -11,9 +11,9 @@
             android:grantUriPermissions="true"
             android:exported="true"
             android:permission="android.permission.MANAGE_DOCUMENTS">
-            <meta-data
-                android:name="android.content.DOCUMENT_PROVIDER"
-                android:value="true" />
+            <intent-filter>
+                <action android:name="android.content.action.DOCUMENTS_PROVIDER" />
+            </intent-filter>
         </provider>
 
         <!-- TODO: find a better place for tests to live -->
@@ -24,9 +24,9 @@
             android:exported="true"
             android:permission="android.permission.MANAGE_DOCUMENTS"
             android:enabled="false">
-            <meta-data
-                android:name="android.content.DOCUMENT_PROVIDER"
-                android:value="true" />
+            <intent-filter>
+                <action android:name="android.content.action.DOCUMENTS_PROVIDER" />
+            </intent-filter>
         </provider>
     </application>
 </manifest>