Expose more gestures to ContentViewCore.GestureStateListeners

* Let ContentViewCore manage more than one GestureStateListener.
* Change GestureStateListener to be an empty implementation.
* ContentViewCore alerts its GestureStateListeners of any scrolls
  or flings, and alerts it of changes in the vertical scroll offset
  or extent.  That last bit is admittedly a bit strange to put in
  the GestureStateListener, but it's going to be listening to starts
  and stops already anyway...

Downstream CL that uses it: https://chrome-internal-review.googlesource.com/#/c/152640/
BUG=332281

Review URL: https://codereview.chromium.org/145953005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247825 0039d316-1c4b-4281-b951-d872f2087c98

android_webview/java/src/org/chromium/android_webview/AwContents.java

@@ -48,6 +48,7 @@ import org.chromium.content.browser.LoadUrlParams;
 import org.chromium.content.browser.NavigationHistory;
 import org.chromium.content.browser.PageTransitionTypes;
 import org.chromium.content.common.CleanupReference;
+import org.chromium.content_public.browser.GestureStateListener;
 import org.chromium.ui.base.ActivityWindowAndroid;
 import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.gfx.DeviceDisplayInfo;
@@ -382,7 +383,7 @@ public class AwContents {
     }
 
     //--------------------------------------------------------------------------------------------
-    private class AwGestureStateListener implements ContentViewCore.GestureStateListener {
+    private class AwGestureStateListener extends GestureStateListener {
         @Override
         public void onPinchGestureStart() {
             // While it's possible to re-layout the view during a pinch gesture, the effect is very
@@ -400,7 +401,8 @@ public class AwContents {
         }
 
         @Override
-        public void onFlingStartGesture(int velocityX, int velocityY) {
+        public void onFlingStartGesture(
+                int velocityX, int velocityY, int scrollOffsetY, int scrollExtentY) {
             mScrollOffsetManager.onFlingStartGesture(velocityX, velocityY);
         }
 
@@ -517,7 +519,7 @@ public class AwContents {
 
     private static ContentViewCore createAndInitializeContentViewCore(ViewGroup containerView,
             InternalAccessDelegate internalDispatcher, int nativeWebContents,
-            ContentViewCore.GestureStateListener pinchGestureStateListener,
+            GestureStateListener gestureStateListener,
             ContentViewClient contentViewClient,
             ContentViewCore.ZoomControlsDelegate zoomControlsDelegate) {
         Context context = containerView.getContext();
@@ -526,7 +528,7 @@ public class AwContents {
                 context instanceof Activity ?
                         new ActivityWindowAndroid((Activity) context) :
                         new WindowAndroid(context.getApplicationContext()));
-        contentViewCore.setGestureStateListener(pinchGestureStateListener);
+        contentViewCore.addGestureStateListener(gestureStateListener);
         contentViewCore.setContentViewClient(contentViewClient);
         contentViewCore.setZoomControlsDelegate(zoomControlsDelegate);
         return contentViewCore;

android_webview/javatests/src/org/chromium/android_webview/test/AndroidScrollIntegrationTest.java

@@ -13,8 +13,8 @@ import org.chromium.android_webview.test.util.AwTestTouchUtils;
 import org.chromium.android_webview.test.util.CommonResources;
 import org.chromium.android_webview.test.util.JavascriptEventObserver;
 import org.chromium.base.test.util.Feature;
-import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content.browser.test.util.CallbackHelper;
+import org.chromium.content_public.browser.GestureStateListener;
 import org.chromium.ui.gfx.DeviceDisplayInfo;
 
 import java.util.concurrent.Callable;
@@ -669,7 +669,7 @@ public class AndroidScrollIntegrationTest extends AwTestBase {
         }
     }
 
-    private static class TestGestureStateListener implements ContentViewCore.GestureStateListener {
+    private static class TestGestureStateListener extends GestureStateListener {
         private CallbackHelper mOnScrollUpdateGestureConsumedHelper = new CallbackHelper();
 
         public CallbackHelper getOnScrollUpdateGestureConsumedHelper() {
@@ -685,7 +685,8 @@ public class AndroidScrollIntegrationTest extends AwTestBase {
         }
 
         @Override
-        public void onFlingStartGesture(int velocityX, int velocityY) {
+        public void onFlingStartGesture(
+                int velocityX, int velocityY, int scrollOffsetY, int scrollExtentY) {
         }
 
         @Override
@@ -726,7 +727,7 @@ public class AndroidScrollIntegrationTest extends AwTestBase {
         getInstrumentation().runOnMainSync(new Runnable() {
             @Override
             public void run() {
-                testContainerView.getContentViewCore().setGestureStateListener(
+                testContainerView.getContentViewCore().addGestureStateListener(
                         testGestureStateListener);
             }
         });

content/public/android/java/src/org/chromium/content/browser/ContentViewClient.java

@@ -180,35 +180,4 @@ public class ContentViewClient {
         return false;
     }
 
-    /**
-     * Called when a fling start event is sent. Note: onFlingStopped() of the previous
-     * fling may be called after onFlingStarted() of the current fling, so if the
-     * client wants to manage the fling status, a counter should be used.
-     */
-    public void onFlingStarted() {
-    }
-
-    /**
-     * Called when a fling is stopped, or a fling start event didn't trigger a fling.
-     */
-    public void onFlingStopped() {
-    }
-
-    /**
-     * Called when a scroll gesture has begun.
-     */
-    public void onScrollBeginEvent() {
-    }
-
-    /**
-     * Called when a scroll gesture has ended.
-     */
-    public void onScrollEndEvent() {
-    }
-
-    /**
-     * Called when the scroll offsets or viewport dimensions may have changed.
-     */
-    public void onScrollOrViewportChanged() {
-    }
 }

content/public/android/java/src/org/chromium/content/browser/ContentViewCore.java

@@ -53,6 +53,8 @@ import com.google.common.annotations.VisibleForTesting;
 import org.chromium.base.CalledByNative;
 import org.chromium.base.CommandLine;
 import org.chromium.base.JNINamespace;
+import org.chromium.base.ObserverList;
+import org.chromium.base.ObserverList.RewindableIterator;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.WeakContext;
 import org.chromium.content.R;
@@ -69,6 +71,7 @@ import org.chromium.content.browser.input.SelectPopupDialog;
 import org.chromium.content.browser.input.SelectPopupItem;
 import org.chromium.content.browser.input.SelectionHandleController;
 import org.chromium.content.common.ContentSwitches;
+import org.chromium.content_public.browser.GestureStateListener;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.ui.base.ViewAndroid;
 import org.chromium.ui.base.ViewAndroidDelegate;
@@ -181,45 +184,6 @@ public class ContentViewCore
         boolean super_awakenScrollBars(int startDelay, boolean invalidate);
     }
 
-    /**
-     * An interface that allows the embedder to be notified of events and state changes related to
-     * gesture processing.
-     */
-    public interface GestureStateListener {
-        /**
-         * Called when the pinch gesture starts.
-         */
-        void onPinchGestureStart();
-
-        /**
-         * Called when the pinch gesture ends.
-         */
-        void onPinchGestureEnd();
-
-        /**
-         * Called when the fling gesture is sent.
-         */
-        void onFlingStartGesture(int vx, int vy);
-
-        /**
-         * Called when the fling cancel gesture is sent.
-         */
-        void onFlingCancelGesture();
-
-        /**
-         * Called when a fling event was not handled by the renderer.
-         */
-        void onUnhandledFlingStartEvent();
-
-        /**
-         * Called to indicate that a scroll update gesture had been consumed by the page.
-         * This callback is called whenever any layer is scrolled (like a frame or div). It is
-         * not called when a JS touch handler consumes the event (preventDefault), it is not called
-         * for JS-initiated scrolling.
-         */
-        void onScrollUpdateGestureConsumed();
-    }
-
     /**
      * An interface for controlling visibility and state of embedder-provided zoom controls.
      */
@@ -371,7 +335,8 @@ public class ContentViewCore
     private boolean mInForeground = false;
 
     private ContentViewGestureHandler mContentViewGestureHandler;
-    private GestureStateListener mGestureStateListener;
+    private final ObserverList<GestureStateListener> mGestureStateListeners;
+    private final RewindableIterator<GestureStateListener> mGestureStateListenersIterator;
     private ZoomManager mZoomManager;
     private ZoomControlsDelegate mZoomControlsDelegate;
 
@@ -500,6 +465,8 @@ public class ContentViewCore
         mInsertionHandlePoint = mRenderCoordinates.createNormalizedPoint();
         mAccessibilityManager = (AccessibilityManager)
                 getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
+        mGestureStateListeners = new ObserverList<GestureStateListener>();
+        mGestureStateListenersIterator = mGestureStateListeners.rewindableIterator();
     }
 
     /**
@@ -869,6 +836,7 @@ public class ContentViewCore
         mJavaScriptInterfaces.clear();
         mRetainedJavaScriptObjects.clear();
         unregisterAccessibilityContentObserver();
+        mGestureStateListeners.clear();
     }
 
     private void unregisterAccessibilityContentObserver() {
@@ -1293,35 +1261,38 @@ public class ContentViewCore
     @SuppressWarnings("unused")
     @CalledByNative
     private void onFlingStartEventAck(int ackResult) {
-        if (ackResult == ContentViewGestureHandler.INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS
-                && mGestureStateListener != null) {
-            mGestureStateListener.onUnhandledFlingStartEvent();
+        if (ackResult == ContentViewGestureHandler.INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS) {
+            for (mGestureStateListenersIterator.rewind();
+                    mGestureStateListenersIterator.hasNext();) {
+                mGestureStateListenersIterator.next().onUnhandledFlingStartEvent();
+            }
         }
         if (ackResult != ContentViewGestureHandler.INPUT_EVENT_ACK_STATE_CONSUMED) {
             // No fling happened for the fling start event.
             // Cancel the fling status set when sending GestureFlingStart.
-            getContentViewClient().onFlingStopped();
+            updateGestureStateListener(ContentViewGestureHandler.GESTURE_FLING_END, null);
         }
     }
 
     @SuppressWarnings("unused")
     @CalledByNative
     private void onScrollBeginEventAck() {
-        getContentViewClient().onScrollBeginEvent();
+        updateGestureStateListener(ContentViewGestureHandler.GESTURE_SCROLL_START, null);
     }
 
     @SuppressWarnings("unused")
     @CalledByNative
     private void onScrollUpdateGestureConsumed() {
-        if (mGestureStateListener != null) {
-            mGestureStateListener.onScrollUpdateGestureConsumed();
+        for (mGestureStateListenersIterator.rewind();
+                mGestureStateListenersIterator.hasNext();) {
+            mGestureStateListenersIterator.next().onScrollUpdateGestureConsumed();
         }
     }
 
     @SuppressWarnings("unused")
     @CalledByNative
     private void onScrollEndEventAck() {
-        getContentViewClient().onScrollEndEvent();
+        updateGestureStateListener(ContentViewGestureHandler.GESTURE_SCROLL_END, null);
     }
 
     private void reportActionAfterDoubleTapUMA(int type) {
@@ -1379,7 +1350,6 @@ public class ContentViewCore
                 nativeScrollEnd(mNativeContentViewCore, timeMs);
                 return true;
             case ContentViewGestureHandler.GESTURE_FLING_START:
-                mContentViewClient.onFlingStarted();
                 nativeFlingStart(mNativeContentViewCore, timeMs, x, y,
                         b.getInt(ContentViewGestureHandler.VELOCITY_X, 0),
                         b.getInt(ContentViewGestureHandler.VELOCITY_Y, 0));
@@ -1427,30 +1397,61 @@ public class ContentViewCore
                 UMAActionAfterDoubleTap.COUNT);
     }
 
-    public void setGestureStateListener(GestureStateListener pinchGestureStateListener) {
-        mGestureStateListener = pinchGestureStateListener;
+    /**
+     * Add a listener that gets alerted on gesture state changes.
+     * @param listener Listener to add.
+     */
+    public void addGestureStateListener(GestureStateListener listener) {
+        mGestureStateListeners.addObserver(listener);
     }
 
-    void updateGestureStateListener(int gestureType, Bundle b) {
-        if (mGestureStateListener == null) return;
+    /**
+     * Removes a listener that was added to watch for gesture state changes.
+     * @param listener Listener to remove.
+     */
+    public void removeGestureStateListener(GestureStateListener listener) {
+        mGestureStateListeners.removeObserver(listener);
+    }
 
-        switch (gestureType) {
-            case ContentViewGestureHandler.GESTURE_PINCH_BEGIN:
-                mGestureStateListener.onPinchGestureStart();
-                break;
-            case ContentViewGestureHandler.GESTURE_PINCH_END:
-                mGestureStateListener.onPinchGestureEnd();
-                break;
-            case ContentViewGestureHandler.GESTURE_FLING_START:
-                mGestureStateListener.onFlingStartGesture(
-                        b.getInt(ContentViewGestureHandler.VELOCITY_X, 0),
-                        b.getInt(ContentViewGestureHandler.VELOCITY_Y, 0));
-                break;
-            case ContentViewGestureHandler.GESTURE_FLING_CANCEL:
-                mGestureStateListener.onFlingCancelGesture();
-                break;
-            default:
-                break;
+    void updateGestureStateListener(int gestureType, Bundle b) {
+        for (mGestureStateListenersIterator.rewind();
+                mGestureStateListenersIterator.hasNext();) {
+            GestureStateListener listener = mGestureStateListenersIterator.next();
+            switch (gestureType) {
+                case ContentViewGestureHandler.GESTURE_PINCH_BEGIN:
+                    listener.onPinchGestureStart();
+                    break;
+                case ContentViewGestureHandler.GESTURE_PINCH_END:
+                    listener.onPinchGestureEnd();
+                    break;
+                case ContentViewGestureHandler.GESTURE_FLING_START:
+                    listener.onFlingStartGesture(
+                            b.getInt(ContentViewGestureHandler.VELOCITY_X, 0),
+                            b.getInt(ContentViewGestureHandler.VELOCITY_Y, 0),
+                            computeVerticalScrollOffset(),
+                            computeVerticalScrollExtent());
+                    break;
+                case ContentViewGestureHandler.GESTURE_FLING_END:
+                    listener.onFlingEndGesture(
+                            computeVerticalScrollOffset(),
+                            computeVerticalScrollExtent());
+                    break;
+                case ContentViewGestureHandler.GESTURE_FLING_CANCEL:
+                    listener.onFlingCancelGesture();
+                    break;
+                case ContentViewGestureHandler.GESTURE_SCROLL_START:
+                    listener.onScrollStarted(
+                            computeVerticalScrollOffset(),
+                            computeVerticalScrollExtent());
+                    break;
+                case ContentViewGestureHandler.GESTURE_SCROLL_END:
+                    listener.onScrollEnded(
+                            computeVerticalScrollOffset(),
+                            computeVerticalScrollExtent());
+                    break;
+                default:
+                    break;
+            }
         }
     }
 
@@ -2444,7 +2445,12 @@ public class ContentViewCore
         onRenderCoordinatesUpdated();
 
         if (scrollChanged || contentOffsetChanged) {
-            getContentViewClient().onScrollOrViewportChanged();
+            for (mGestureStateListenersIterator.rewind();
+                    mGestureStateListenersIterator.hasNext();) {
+                mGestureStateListenersIterator.next().onScrollOffsetOrExtentChanged(
+                        computeVerticalScrollOffset(),
+                        computeVerticalScrollExtent());
+            }
         }
 
         if (needTemporarilyHideHandles) temporarilyHideTextHandles();
@@ -3215,7 +3221,7 @@ public class ContentViewCore
 
     @CalledByNative
     private void onNativeFlingStopped() {
-        getContentViewClient().onFlingStopped();
+        updateGestureStateListener(ContentViewGestureHandler.GESTURE_FLING_END, null);
     }
 
     private native WebContents nativeGetWebContentsAndroid(long nativeContentViewCoreImpl);

content/public/android/java/src/org/chromium/content/browser/ContentViewGestureHandler.java

@@ -208,12 +208,13 @@ class ContentViewGestureHandler implements LongPressDelegate {
     static final int GESTURE_SCROLL_END = 8;
     static final int GESTURE_FLING_START = 9;
     static final int GESTURE_FLING_CANCEL = 10;
-    static final int GESTURE_PINCH_BEGIN = 11;
-    static final int GESTURE_PINCH_BY = 12;
-    static final int GESTURE_PINCH_END = 13;
-    static final int GESTURE_TAP_CANCEL = 14;
-    static final int GESTURE_LONG_TAP = 15;
-    static final int GESTURE_TAP_DOWN = 16;
+    static final int GESTURE_FLING_END = 11;
+    static final int GESTURE_PINCH_BEGIN = 12;
+    static final int GESTURE_PINCH_BY = 13;
+    static final int GESTURE_PINCH_END = 14;
+    static final int GESTURE_TAP_CANCEL = 15;
+    static final int GESTURE_LONG_TAP = 16;
+    static final int GESTURE_TAP_DOWN = 17;
 
     // These have to be kept in sync with content/port/common/input_event_ack_state.h
     static final int INPUT_EVENT_ACK_STATE_UNKNOWN = 0;

content/public/android/java/src/org/chromium/content_public/browser/GestureStateListener.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 org.chromium.content_public.browser;
+
+/**
+ * A class that is notified of events and state changes related to gesture processing from
+ * the ContentViewCore.
+ */
+public class GestureStateListener {
+    /**
+     * Called when the pinch gesture starts.
+     */
+    public void onPinchGestureStart() {}
+
+    /**
+     * Called when the pinch gesture ends.
+     */
+    public void onPinchGestureEnd() {}
+
+    /**
+     * Called when the fling gesture is sent.
+     */
+    public void onFlingStartGesture(int vx, int vy, int scrollOffsetY, int scrollExtentY) {}
+
+    /**
+     * Called when the fling cancel gesture is sent.
+     */
+    public void onFlingCancelGesture() {}
+
+    /**
+     * Called when a fling has ended.
+     */
+    public void onFlingEndGesture(int scrollOffsetY, int scrollExtentY) {}
+
+    /**
+     * Called when a fling event was not handled by the renderer.
+     */
+    public void onUnhandledFlingStartEvent() {}
+
+    /**
+     * Called to indicate that a scroll update gesture had been consumed by the page.
+     * This callback is called whenever any layer is scrolled (like a frame or div). It is
+     * not called when a JS touch handler consumes the event (preventDefault), it is not called
+     * for JS-initiated scrolling.
+     */
+    public void onScrollUpdateGestureConsumed() {}
+
+    /*
+     * Called when a scroll gesture has started.
+     */
+    public void onScrollStarted(int scrollOffsetY, int scrollExtentY) {}
+
+    /*
+     * Called when a scroll gesture has stopped.
+     */
+    public void onScrollEnded(int scrollOffsetY, int scrollExtentY) {}
+
+    /*
+     * Called when the scroll offsets or extents may have changed.
+     */
+    public void onScrollOffsetOrExtentChanged(int scrollOffsetY, int scrollExtentY) {}
+}
\ No newline at end of file