Upstream: ChildProcessLauncher connects renderer processes of WebAPKs.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java

 // Copyright 2016 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.webapps;
 
 import android.content.Intent;
 
+import org.chromium.base.ContextUtils;
+import org.chromium.base.library_loader.LibraryProcessType;
+import org.chromium.chrome.browser.ChromeApplication;
 import org.chromium.chrome.browser.ShortcutHelper;
+import org.chromium.content.browser.ChildProcessCreationParams;
 import org.chromium.content_public.browser.LoadUrlParams;
 import org.chromium.ui.base.PageTransition;
 
 /**
  * An Activity is designed for WebAPKs (native Android apps) and displays a webapp in a nearly
  * UI-less Chrome.
  */
 public class WebApkActivity extends WebappActivity {
     @Override
     protected void onNewIntent(Intent intent) {
@@ skipping 12 matching lines @@
                     new LoadUrlParams(overrideUrl, PageTransition.AUTO_TOPLEVEL));
         }
     }
 
     @Override
     protected void initializeSplashScreenWidgets(final int backgroundColor) {
         // TODO(hanxi): Removes this function and use {@link WebApkActivity}'s implementation
         // when WebAPKs are registered in WebappRegistry.
         initializeSplashScreenWidgets(backgroundColor, null);
     }
+
+    @Override
+    public void onResume() {
+        super.onResume();
+        // WebAPK hosts Chrome's renderer processes by declaring Chrome' renderer service in its
+        // AndroidManifest.xml. We set WebAPK's child process creation parameter to let the
+        // {@link ChildProcessLauncher} knows which application's renderer service to connect.

[pkotwicz, 2016/05/27 21:10:13]

Nit: connect to

Can you update this comment. I do not understand what the "WebAPK child process
creation parameter" is.

[Xi Han, 2016/05/27 21:31:39]

Done.

+        initializeChildProcessCreationParams(true);
+    }
+
+    @Override
+    protected void initializeChildProcessCreationParams() {
+        // TODO(hanxi): crbug.com/611842. Investigates whether this function works for multiple
+        // window or with --site-per-process enabled.

[pkotwicz, 2016/05/27 21:10:13]

window -> windows

[Xi Han, 2016/05/27 21:31:39]

Done.

+        initializeChildProcessCreationParams(true);
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        initializeChildProcessCreationParams(false);
+    }
+

[pkotwicz, 2016/05/27 21:10:13]

Nit: isForWebApk

Please add a comment to this function

[Xi Han, 2016/05/27 21:31:39]

Done.

+    private void initializeChildProcessCreationParams(boolean isforWebApk) {
+        ChromeApplication chrome = (ChromeApplication) ContextUtils.getApplicationContext();
+        ChildProcessCreationParams params = chrome.getChildProcessCreationParams();
+        if (isforWebApk) {
+            params = new ChildProcessCreationParams(getWebappInfo().webApkPackageName(),
+                    params.getExtraBindFlags(), LibraryProcessType.PROCESS_WEBAPK_CHILD);
+        }
+        ChildProcessCreationParams.set(params);
+    }
 }