Upstream: ChildProcessLauncher connects renderer processes of WebAPKs.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
index 2cd5ea50d829ef8efec3498d910f8cdb120fc8a4..63b76a6d714e390ab2a4609287139631480111df 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
@@ -6,7 +6,11 @@ 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;
 
@@ -39,4 +43,36 @@ public class WebApkActivity extends WebappActivity {
         // 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.
+        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.
+        initializeChildProcessCreationParams(true);
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        initializeChildProcessCreationParams(false);
+    }
+
+    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);
+    }
 }