weblayer: adds plumbing for BrowserObserver

Here's the set of classes/changes:

weblayer_private.BrowserControllerClient: this is a singleton that is supplied
when creating BrowserControllerImpl. It will duplicate the C++ BrowserObserver
interface along with any other server->client calls we want.

BrowserController: supplies an implementation (as an inner class) of
BrowserControllerClient to BrowserControllerImpl. BrowserController's inner
class forwards calls to BrowserObservers.

BrowserObserverProxy: there is a C++ and Java class with this name. The two
are tightly coupled. The C++ side implements BrowserObserver and forwards to the
java side. The java side forwards to BrowserControllerClient.

BUG=none
TEST=none

Change-Id: I2817149224f4ac2045769c4ce0c3f81040dc7507
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1772501
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691007}

weblayer/BUILD.gn

@@ -134,6 +134,10 @@ jumbo_static_library("weblayer_lib") {
       "//ui/android",
       "//weblayer/browser/java:jni",
     ]
+    sources += [
+      "browser/browser_observer_proxy.cc",
+      "browser/browser_observer_proxy.h",
+    ]
   }
 
   if (toolkit_views) {

weblayer/browser/browser_observer_proxy.cc

+// Copyright 2019 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.
+
+#include "weblayer/browser/browser_observer_proxy.h"
+
+#include "base/android/jni_string.h"
+#include "url/gurl.h"
+#include "weblayer/browser/browser_controller_impl.h"
+#include "weblayer/browser/java/jni/BrowserObserverProxy_jni.h"
+
+using base::android::AttachCurrentThread;
+using base::android::ConvertUTF8ToJavaString;
+using base::android::ScopedJavaLocalRef;
+
+namespace weblayer {
+
+BrowserObserverProxy::BrowserObserverProxy(
+    JNIEnv* env,
+    jobject obj,
+    BrowserController* browser_controller)
+    : browser_controller_(browser_controller), java_observer_(env, obj) {
+  browser_controller_->AddObserver(this);
+}
+
+BrowserObserverProxy::~BrowserObserverProxy() {
+  browser_controller_->RemoveObserver(this);
+}
+
+void BrowserObserverProxy::DisplayedURLChanged(const GURL& url) {
+  JNIEnv* env = AttachCurrentThread();
+  ScopedJavaLocalRef<jstring> jstring_url(
+      ConvertUTF8ToJavaString(env, url.spec()));
+  Java_BrowserObserverProxy_displayURLChanged(env, java_observer_, jstring_url);
+}
+
+void BrowserObserverProxy::LoadingStateChanged(bool is_loading,
+                                               bool to_different_document) {}
+
+void BrowserObserverProxy::FirstContentfulPaint() {}
+
+static jlong JNI_BrowserObserverProxy_CreateBrowserObsererProxy(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& proxy,
+    jlong browser_controller) {
+  return reinterpret_cast<jlong>(new BrowserObserverProxy(
+      env, proxy,
+      reinterpret_cast<BrowserControllerImpl*>(browser_controller)));
+}
+
+static void JNI_BrowserObserverProxy_DeleteBrowserObserverProxy(JNIEnv* env,
+                                                                jlong proxy) {
+  delete reinterpret_cast<BrowserObserverProxy*>(proxy);
+}
+
+}  // namespace weblayer

weblayer/browser/browser_observer_proxy.h

+// Copyright 2019 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.
+
+#ifndef WEBLAYER_BROWSER_BROWSER_OBSERVER_PROXY_H_
+#define WEBLAYER_BROWSER_BROWSER_OBSERVER_PROXY_H_
+
+#include <jni.h>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/macros.h"
+#include "weblayer/public/browser_observer.h"
+
+namespace weblayer {
+
+class BrowserController;
+
+// BrowserObserverProxy forwards all BrowserObserver functions to the Java
+// side. There is one BrowserObserverProxy per BrowserController.
+class BrowserObserverProxy : public BrowserObserver {
+ public:
+  BrowserObserverProxy(JNIEnv* env,
+                       jobject obj,
+                       BrowserController* browser_controller);
+  ~BrowserObserverProxy() override;
+
+  // BrowserObserver:
+  void DisplayedURLChanged(const GURL& url) override;
+  void LoadingStateChanged(bool is_loading,
+                           bool to_different_document) override;
+  void FirstContentfulPaint() override;
+
+ private:
+  BrowserController* browser_controller_;
+  base::android::ScopedJavaGlobalRef<jobject> java_observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserObserverProxy);
+};
+
+}  // namespace weblayer
+
+#endif  // WEBLAYER_BROWSER_BROWSER_OBSERVER_PROXY_H_

weblayer/browser/java/BUILD.gn

@@ -7,7 +7,9 @@ import("//build/config/android/rules.gni")
 
 android_library("java") {
   java_files = [
+    "org/chromium/weblayer_private/BrowserControllerClient.java",
     "org/chromium/weblayer_private/BrowserControllerImpl.java",
+    "org/chromium/weblayer_private/BrowserObserverProxy.java",
     "org/chromium/weblayer_private/ProfileImpl.java",
     "org/chromium/weblayer_private/WebLayerImpl.java",
   ]
@@ -24,6 +26,7 @@ android_library("java") {
 generate_jni("jni") {
   sources = [
     "org/chromium/weblayer_private/BrowserControllerImpl.java",
+    "org/chromium/weblayer_private/BrowserObserverProxy.java",
     "org/chromium/weblayer_private/ProfileImpl.java",
   ]
 }

weblayer/browser/java/org/chromium/weblayer_private/BrowserControllerClient.java

+// Copyright 2019 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.weblayer_private;
+
+/**
+ * Interface used by BrowserController to inform the client of changes. This largely duplicates the
+ *  BrowserObserver interface, but is a singleton to avoid unnecessary IPC.
+ */
+public interface BrowserControllerClient { public void displayURLChanged(String url); }

weblayer/browser/java/org/chromium/weblayer_private/BrowserControllerImpl.java

@@ -18,14 +18,13 @@ import org.chromium.ui.base.ViewAndroidDelegate;
 
 @JNINamespace("weblayer")
 public final class BrowserControllerImpl {
-    // TODO: should there be one tag for all this code?
-    private static final String TAG = "WebLayer";
     private long mNativeBrowserController;
 
     private ActivityWindowAndroid mWindowAndroid;
     private ContentViewRenderView mContentView;
     private ProfileImpl mProfile;
     private WebContents mWebContents;
+    private BrowserObserverProxy mBrowserObserverProxy;
 
     private static class InternalAccessDelegateImpl
             implements ViewEventSink.InternalAccessDelegate {
@@ -48,7 +47,8 @@ public final class BrowserControllerImpl {
         public void onScrollChanged(int lPix, int tPix, int oldlPix, int oldtPix) {}
     }
 
-    public BrowserControllerImpl(Activity activity, ProfileImpl profile) {
+    public BrowserControllerImpl(
+            Activity activity, ProfileImpl profile, BrowserControllerClient client) {
         mProfile = profile;
 
         mWindowAndroid = new ActivityWindowAndroid(activity);
@@ -66,9 +66,11 @@ public final class BrowserControllerImpl {
 
         mContentView.setCurrentWebContents(mWebContents);
         mWebContents.onShow();
+        mBrowserObserverProxy = new BrowserObserverProxy(mNativeBrowserController, client);
     }
 
     public void destroy() {
+        mBrowserObserverProxy.destroy();
         nativeDeleteBrowserController(mNativeBrowserController);
         mNativeBrowserController = 0;
     }

weblayer/browser/java/org/chromium/weblayer_private/BrowserObserverProxy.java

+// Copyright 2019 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.weblayer_private;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+@JNINamespace("weblayer")
+public final class BrowserObserverProxy {
+    private long mNativeBrowserObserverProxy;
+    private BrowserControllerClient mClient;
+
+    BrowserObserverProxy(long browserController, BrowserControllerClient client) {
+        mClient = client;
+        mNativeBrowserObserverProxy = nativeCreateBrowserObsererProxy(this, browserController);
+    }
+
+    public void destroy() {
+        nativeDeleteBrowserObserverProxy(mNativeBrowserObserverProxy);
+    }
+
+    @CalledByNative
+    private void displayURLChanged(String string) {
+        mClient.displayURLChanged(string);
+    }
+
+    private static native long nativeCreateBrowserObsererProxy(
+            BrowserObserverProxy proxy, long browserController);
+    private static native void nativeDeleteBrowserObserverProxy(long proxy);
+}

weblayer/public/java/BUILD.gn

@@ -8,6 +8,7 @@ import("//build/config/android/rules.gni")
 android_library("java") {
   java_files = [
     "org/chromium/weblayer/BrowserController.java",
+    "org/chromium/weblayer/BrowserObserver.java",
     "org/chromium/weblayer/NavigationController.java",
     "org/chromium/weblayer/Profile.java",
     "org/chromium/weblayer/WebLayer.java",

weblayer/public/java/org/chromium/weblayer/BrowserController.java

@@ -5,16 +5,24 @@
 package org.chromium.weblayer;
 
 import android.app.Activity;
+import android.net.Uri;
 
+import org.chromium.weblayer_private.BrowserControllerClient;
 import org.chromium.weblayer_private.BrowserControllerImpl;
 
+import java.util.concurrent.CopyOnWriteArrayList;
+
 public final class BrowserController {
-    private BrowserControllerImpl mBrowserController;
-    private NavigationController mNavigationController;
+    private final BrowserControllerImpl mBrowserController;
+    private final NavigationController mNavigationController;
+    // TODO(sky): copy ObserverList from base and use it instead.
+    private final CopyOnWriteArrayList<BrowserObserver> mObservers;
 
     public BrowserController(Activity activity, Profile profile) {
-        mBrowserController = new BrowserControllerImpl(activity, profile.getProfileImpl());
+        mBrowserController = new BrowserControllerImpl(
+                activity, profile.getProfileImpl(), new BrowserClientImpl());
         mNavigationController = new NavigationController(mBrowserController);
+        mObservers = new CopyOnWriteArrayList<BrowserObserver>();
     }
 
     @Override
@@ -25,4 +33,22 @@ public final class BrowserController {
     public NavigationController getNavigationController() {
         return mNavigationController;
     }
+
+    public void addObserver(BrowserObserver observer) {
+        mObservers.add(observer);
+    }
+
+    public void removeObserver(BrowserObserver observer) {
+        mObservers.remove(observer);
+    }
+
+    private final class BrowserClientImpl implements BrowserControllerClient {
+        @Override
+        public void displayURLChanged(String url) {
+            Uri uri = Uri.parse(url);
+            for (BrowserObserver observer : mObservers) {
+                observer.displayURLChanged(uri);
+            }
+        }
+    }
 }

weblayer/public/java/org/chromium/weblayer/BrowserObserver.java

+// Copyright 2019 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.weblayer;
+
+import android.net.Uri;
+
+/**
+ * Informed of interesting events that happen during the lifetime of a BrowserController.
+ */
+public abstract class BrowserObserver {
+    /**
+     * The Uri that should be displayed in the url-bar has updated.
+     */
+    public void displayURLChanged(Uri url) {}
+}