[Android WebView] Add auto-grant permissions to WebViewShell.

Grant certain permissions like video and audio capture in the WebViewShell
mini-browser automatically. This is necessary to be able to test WebRTC
functionality.

BUG=481508

Review URL: https://codereview.chromium.org/1127213005

Cr-Commit-Position: refs/heads/master@{#329647}

android_webview/tools/WebViewShell/AndroidManifest.xml

@@ -16,6 +16,9 @@
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
+    <uses-permission android:name="android.permission.CAMERA"/>
+    <uses-permission android:name="android.permission.RECORD_AUDIO"/>
+    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
 
     <application
         android:icon="@drawable/ic_launcher"

android_webview/tools/WebViewShell/src/org/chromium/webview_shell/WebViewBrowserActivity.java

@@ -13,6 +13,7 @@ import android.view.View;
 import android.view.View.OnKeyListener;
 import android.view.inputmethod.InputMethodManager;
 import android.webkit.GeolocationPermissions;
+import android.webkit.PermissionRequest;
 import android.webkit.WebChromeClient;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
@@ -28,6 +29,9 @@ public class WebViewBrowserActivity extends Activity {
     private EditText mUrlBar;
     private WebView mWebView;
 
+    private static final String[] AUTOMATICALLY_GRANT =
+            { PermissionRequest.RESOURCE_VIDEO_CAPTURE, PermissionRequest.RESOURCE_AUDIO_CAPTURE };
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -51,6 +55,11 @@ public class WebViewBrowserActivity extends Activity {
                     GeolocationPermissions.Callback callback) {
                 callback.invoke(origin, true, false);
             }
+
+            @Override
+            public void onPermissionRequest(PermissionRequest request) {
+                request.grant(AUTOMATICALLY_GRANT);
+            }
         });
 
         mUrlBar = (EditText) findViewById(R.id.url_field);