Prepare to get the multiprocess setting from WebViewDelegate.

android_webview/glue/java/src/com/android/webview/chromium/WebViewDelegateFactory.java

 // Copyright 2014 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 com.android.webview.chromium;
 
 import android.annotation.TargetApi;
 import android.app.Application;
 import android.content.Context;
 import android.content.ContextWrapper;
 import android.content.pm.PackageInfo;
 import android.content.res.AssetManager;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.os.Build;
 import android.os.Trace;
+import android.provider.Settings;
 import android.util.SparseArray;
 import android.view.View;
 
+import org.chromium.base.ContextUtils;
+
 import java.lang.reflect.Method;
 
 /**
  * Factory class for {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate}s.
  *
  * <p>{@link WebViewDelegate com.android.webview.chromium.WebViewDelegate}s provide the same
  * interface as {@link android.webkit.WebViewDelegate android.webkit.WebViewDelegate} but without
  * a dependency on the webkit class. Defining our own
  * {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate} in frameworks/webview
  * allows the WebView apk to be binary compatible with the API 21 version of the framework, in
@@ skipping 45 matching lines @@
         int getPackageId(Resources resources, String packageName);
 
         /** @see android.webkit.WebViewDelegate#getApplication */
         Application getApplication();
 
         /** @see android.webkit.WebViewDelegate#getErrorString */
         String getErrorString(Context context, int errorCode);
 
         /** @see android.webkit.WebViewDelegate#addWebViewAssetPath */
         void addWebViewAssetPath(Context context);
+
+        /** @see android.webkit.WebViewDelegate#isMultiProcessEnabled */
+        boolean isMultiProcessEnabled();
     }
 
     /**
      * Creates a {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate} that proxies
      * requests to the given {@link android.webkit.WebViewDelegate android.webkit.WebViewDelegate}.
      *
      * @return the created delegate
      */
     static WebViewDelegate createProxyDelegate(android.webkit.WebViewDelegate delegate) {
         return new ProxyDelegate(delegate);
     }
 
     /**
      * Creates a {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate} compatible
      * with the API 21 version of the framework in which
      * {@link android.webkit.WebViewDelegate android.webkit.WebViewDelegate} had not yet been
      * introduced.
      *
      * @return the created delegate
      */
     static WebViewDelegate createApi21CompatibilityDelegate() {
         return new Api21CompatibilityDelegate();
     }
 
     /**
      * A {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate} that proxies requests
      * to a {@link android.webkit.WebViewDelegate android.webkit.WebViewDelegate}.
      */
-    private static class ProxyDelegate implements WebViewDelegate {
+    static class ProxyDelegate implements WebViewDelegate {

[boliu, 2017/01/23 16:34:18]

does protected work here too..?

[Torne, 2017/01/23 17:27:30]

Likewise no point.

         android.webkit.WebViewDelegate mDelegate;
 
         ProxyDelegate(android.webkit.WebViewDelegate delegate) {
             mDelegate = delegate;
         }
 
         @Override
         public void setOnTraceEnabledChangeListener(final OnTraceEnabledChangeListener listener) {
             mDelegate.setOnTraceEnabledChangeListener(
                     new android.webkit.WebViewDelegate.OnTraceEnabledChangeListener() {
@@ skipping 67 matching lines @@
             // wrapper here here to avoid calling the getAssets()
             // proxy chain (which we cannot change because it is in
             // WebView framework code).
             mDelegate.addWebViewAssetPath(new ContextWrapper(context) {
                 @Override
                 public AssetManager getAssets() {
                     return getResources().getAssets();
                 }
             });
         }
+
+        @Override
+        public boolean isMultiProcessEnabled() {
+            // Multiprocess requires N or later.

[boliu, 2017/01/23 16:34:18]

I suppose this class was never meant to contain implementation, only call
forwarding, although clearly there are exceptions already..

[Torne, 2017/01/23 17:27:30]

I was considering renaming it to Api22AndUpDelegate or something, but I want to
keep this CL minimal for cherrypicking to M57. If you think that's a good idea I
can do it in a followup.

[boliu, 2017/01/23 17:44:04]

Err, no :p

I meant at callsite, have a if <= N, do this, else, call delegate. The reason we
have this thing at all is because the framework delegate didn't exist in api 21.
Above 21, this should behave exactly like the framework delegate, ie some
methods are only safe to call on certain api levels.

That's my mental model anyway.. doesn't matter much either way, since there's
already other implementation here.

[Torne, 2017/01/24 11:24:01]

I think that's a better idea actually; I'll do it that way instead, which means
the initial version of this upstream just won't do anything..

+            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) return false;
+
+            // Check the multiprocess developer setting.
+            return Settings.Global.getInt(ContextUtils.getApplicationContext().getContentResolver(),
+                    Settings.Global.WEBVIEW_MULTIPROCESS, 0) == 1;
+        }
     }
 
     /**
      * A {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate} compatible with the
      * API 21 version of the framework in which
      * {@link android.webkit.WebViewDelegate android.webkit.WebViewDelegate} had not yet been
      * introduced.
      *
      * <p>This class implements the
      * {@link WebViewDelegate com.android.webview.chromium.WebViewDelegate} functionality by using
@@ skipping 165 matching lines @@
             try {
                 PackageInfo info = (PackageInfo) mGetLoadedPackageInfoMethod.invoke(null);
                 // Avoid calling the ContextWrapper.getAssets() proxy
                 // chain, which can return an unexpected AssetManager.
                 mAddAssetPathMethod.invoke(
                         context.getResources().getAssets(), info.applicationInfo.sourceDir);
             } catch (Exception e) {
                 throw new RuntimeException("Invalid reflection", e);
             }
         }
+
+        @Override
+        public boolean isMultiProcessEnabled() {
+            return false;
+        }
     }
 }