[WebView Support Library] Pass and fetch list of supported features.

We need some way for either side (android support library + chromium) of
the webview support library to tell what features the other side of the
support library supports. We do this by passing a list of integers
across the boundary. These integers will each represent a feature (which
will be defined in a class in the boundary interface package).

Add a single feature to the list of features to support (visual state
callback).

Bug: 740082
Change-Id: I791af590cb846d536d01d63649ab6cfffe558ee9
Reviewed-on: https://chromium-review.googlesource.com/941805
Commit-Queue: Gustav Sennton <gsennton@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542169}

android_webview/support_library/boundary_interfaces/BUILD.gn

@@ -8,12 +8,14 @@ import("//build/config/android/rules.gni")
 android_library("boundary_interface_java") {
   java_files = [
     "src/org/chromium/support_lib_boundary/StaticsBoundaryInterface.java",
+    "src/org/chromium/support_lib_boundary/SupportLibraryInfoBoundaryInterface.java",
     "src/org/chromium/support_lib_boundary/VisualStateCallbackBoundaryInterface.java",
     "src/org/chromium/support_lib_boundary/WebSettingsBoundaryInterface.java",
     "src/org/chromium/support_lib_boundary/WebViewProviderBoundaryInterface.java",
     "src/org/chromium/support_lib_boundary/WebViewProviderFactoryBoundaryInterface.java",
     "src/org/chromium/support_lib_boundary/WebkitToCompatConverterBoundaryInterface.java",
     "src/org/chromium/support_lib_boundary/util/BoundaryInterfaceReflectionUtil.java",
+    "src/org/chromium/support_lib_boundary/util/Features.java",
   ]
 
   proguard_configs = [ "proguard.flags" ]

android_webview/support_library/boundary_interfaces/src/org/chromium/support_lib_boundary/SupportLibraryInfoBoundaryInterface.java

+// Copyright 2018 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.support_lib_boundary;
+
+/**
+ * Contains information about the WebView support library side, e.g. which features are supported on
+ * that side.
+ * This is passed to the WebView APK code on support library initialization.
+ */
+public interface SupportLibraryInfoBoundaryInterface { String[] getSupportedFeatures(); }

android_webview/support_library/boundary_interfaces/src/org/chromium/support_lib_boundary/WebViewProviderFactoryBoundaryInterface.java

@@ -14,4 +14,5 @@ public interface WebViewProviderFactoryBoundaryInterface {
     /* SupportLibraryWebViewChromium */ InvocationHandler createWebView(WebView webview);
     /* SupportLibWebkitToCompatConverter */ InvocationHandler getWebkitToCompatConverter();
     /* StaticsAdapter */ InvocationHandler getStatics();
+    String[] getSupportedFeatures();
 }

android_webview/support_library/boundary_interfaces/src/org/chromium/support_lib_boundary/util/Features.java

+// Copyright 2018 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.support_lib_boundary.util;
+
+/**
+ * Class containing all the features the support library can support.
+ * This class lives in the boundary interface directory so that the Android Support Library and
+ * Chromium can share its definition.
+ */
+public class Features {
+    // This class just contains constants representing features.
+    private Features() {}
+
+    // WebViewCompat.postVisualStateCallback
+    public static final String VISUAL_STATE_CALLBACK = "VISUAL_STATE_CALLBACK";
+}

android_webview/support_library/java/src/org/chromium/support_lib_glue/SupportLibReflectionUtil.java

@@ -20,8 +20,10 @@ public class SupportLibReflectionUtil {
      * Changing the signature of this method will break existing WebView Support Library versions!
      */
     @UsedByReflection("WebView Support Library")
-    public static InvocationHandler createWebViewProviderFactory() {
-        final SupportLibWebViewChromiumFactory factory = new SupportLibWebViewChromiumFactory();
+    public static InvocationHandler createWebViewProviderFactory(
+            /* SupportLibraryInfo */ InvocationHandler supportLibraryInfo) {
+        final SupportLibWebViewChromiumFactory factory =
+                new SupportLibWebViewChromiumFactory(supportLibraryInfo);
         return BoundaryInterfaceReflectionUtil.createInvocationHandlerFor(factory);
     }
 }

android_webview/support_library/java/src/org/chromium/support_lib_glue/SupportLibWebViewChromiumFactory.java

@@ -15,8 +15,10 @@ import com.android.webview.chromium.WebViewChromiumAwInit;
 import com.android.webview.chromium.WebkitToSharedGlueConverter;
 
 import org.chromium.support_lib_boundary.StaticsBoundaryInterface;
+import org.chromium.support_lib_boundary.SupportLibraryInfoBoundaryInterface;
 import org.chromium.support_lib_boundary.WebViewProviderFactoryBoundaryInterface;
 import org.chromium.support_lib_boundary.util.BoundaryInterfaceReflectionUtil;
+import org.chromium.support_lib_boundary.util.Features;
 
 import java.lang.reflect.InvocationHandler;
 import java.util.List;
@@ -28,14 +30,23 @@ class SupportLibWebViewChromiumFactory implements WebViewProviderFactoryBoundary
     // SupportLibWebkitToCompatConverterAdapter
     private final InvocationHandler mCompatConverterAdapter;
     private final WebViewChromiumAwInit mAwInit;
+    private final String[] mSupportLibrarySupportedFeatures;
+    private final String[] mWebViewSupportedFeatures =
+            new String[] {Features.VISUAL_STATE_CALLBACK};
 
     // Initialization guarded by mAwInit.getLock()
     private InvocationHandler mStatics;
 
-    public SupportLibWebViewChromiumFactory() {
+    public SupportLibWebViewChromiumFactory(
+            /* SupportLibraryInfo */ InvocationHandler supportLibraryInfo) {
         mCompatConverterAdapter = BoundaryInterfaceReflectionUtil.createInvocationHandlerFor(
                 new SupportLibWebkitToCompatConverterAdapter());
         mAwInit = WebkitToSharedGlueConverter.getGlobalAwInit();
+        mSupportLibrarySupportedFeatures =
+                BoundaryInterfaceReflectionUtil
+                        .castToSuppLibClass(
+                                SupportLibraryInfoBoundaryInterface.class, supportLibraryInfo)
+                        .getSupportedFeatures();
     }
 
     @Override
@@ -85,4 +96,9 @@ class SupportLibWebViewChromiumFactory implements WebViewProviderFactoryBoundary
         }
         return mStatics;
     }
+
+    @Override
+    public String[] getSupportedFeatures() {
+        return mWebViewSupportedFeatures;
+    }
 }