weblayer: update top-control scrolling

Top-controls scrolling was missing a couple of key things:
. when the top-controls are completely visible (and no gesture/scroll is
  underway), the height of the Webcontents should shrink.
. DoBrowserControlsShrinkRendererSize() should not change value while
  a gesture/scroll is underway (otherwise the scrollbar bounces around).

The logic added should match that of Chrome.

BUG=1017204
TEST=none

Change-Id: I2185409244e278dfd230499b65ed2d953eda6d70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1880589
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709559}

weblayer/browser/browser_controller_impl.cc

@@ -58,6 +58,15 @@ void HandleJavaScriptResult(
 
 }  // namespace
 
+#if defined(OS_ANDROID)
+BrowserControllerImpl::BrowserControllerImpl(
+    ProfileImpl* profile,
+    const base::android::JavaParamRef<jobject>& java_impl)
+    : BrowserControllerImpl(profile) {
+  java_impl_ = java_impl;
+}
+#endif
+
 BrowserControllerImpl::BrowserControllerImpl(ProfileImpl* profile)
     : profile_(profile) {
 #if defined(OS_ANDROID)
@@ -142,10 +151,12 @@ void BrowserControllerImpl::AttachToView(views::WebView* web_view) {
 #endif
 
 #if defined(OS_ANDROID)
-static jlong JNI_BrowserControllerImpl_CreateBrowserController(JNIEnv* env,
-                                                               jlong profile) {
-  return reinterpret_cast<intptr_t>(
-      new BrowserControllerImpl(reinterpret_cast<ProfileImpl*>(profile)));
+static jlong JNI_BrowserControllerImpl_CreateBrowserController(
+    JNIEnv* env,
+    jlong profile,
+    const base::android::JavaParamRef<jobject>& java_impl) {
+  return reinterpret_cast<intptr_t>(new BrowserControllerImpl(
+      reinterpret_cast<ProfileImpl*>(profile), java_impl));
 }
 
 static void JNI_BrowserControllerImpl_DeleteBrowserController(
@@ -216,7 +227,12 @@ int BrowserControllerImpl::GetTopControlsHeight() {
 
 bool BrowserControllerImpl::DoBrowserControlsShrinkRendererSize(
     const content::WebContents* web_contents) {
-  return true;
+#if defined(OS_ANDROID)
+  return Java_BrowserControllerImpl_doBrowserControlsShrinkRendererSize(
+      base::android::AttachCurrentThread(), java_impl_);
+#else
+  return false;
+#endif
 }
 
 bool BrowserControllerImpl::EmbedsFullscreenWidget() {

weblayer/browser/browser_controller_impl.h

@@ -36,6 +36,11 @@ class BrowserControllerImpl : public BrowserController,
                               public content::WebContentsDelegate,
                               public content::WebContentsObserver {
  public:
+  // TODO(sky): investigate a better way to not have so many ifdefs.
+#if defined(OS_ANDROID)
+  BrowserControllerImpl(ProfileImpl* profile,
+                        const base::android::JavaParamRef<jobject>& java_impl);
+#endif
   explicit BrowserControllerImpl(ProfileImpl* profile);
   ~BrowserControllerImpl() override;
 
@@ -115,6 +120,7 @@ class BrowserControllerImpl : public BrowserController,
   base::ObserverList<BrowserObserver>::Unchecked observers_;
 #if defined(OS_ANDROID)
   TopControlsContainerView* top_controls_container_view_ = nullptr;
+  base::android::ScopedJavaGlobalRef<jobject> java_impl_;
 #endif
 
   bool is_fullscreen_ = false;

weblayer/browser/java/BUILD.gn

@@ -21,6 +21,7 @@ android_library("java") {
     "org/chromium/weblayer_private/BrowserFragmentControllerImpl.java",
     "org/chromium/weblayer_private/BrowserFragmentImpl.java",
     "org/chromium/weblayer_private/BrowserObserverProxy.java",
+    "org/chromium/weblayer_private/ChildProcessServiceImpl.java",
     "org/chromium/weblayer_private/ContentView.java",
     "org/chromium/weblayer_private/ContentViewRenderView.java",
     "org/chromium/weblayer_private/DownloadDelegateProxy.java",
@@ -30,10 +31,10 @@ android_library("java") {
     "org/chromium/weblayer_private/ProfileImpl.java",
     "org/chromium/weblayer_private/FragmentWindowAndroid.java",
     "org/chromium/weblayer_private/ProfileManager.java",
+    "org/chromium/weblayer_private/RemoteFragmentImpl.java",
+    "org/chromium/weblayer_private/WebContentsGestureStateTracker.java",
     "org/chromium/weblayer_private/TopControlsContainerView.java",
     "org/chromium/weblayer_private/WebLayerImpl.java",
-    "org/chromium/weblayer_private/ChildProcessServiceImpl.java",
-    "org/chromium/weblayer_private/RemoteFragmentImpl.java",
   ]
 
   deps = [

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

@@ -14,6 +14,7 @@ import android.webkit.ValueCallback;
 import android.widget.FrameLayout;
 
 import org.chromium.base.Callback;
+import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.NativeMethods;
 import org.chromium.content_public.browser.ViewEventSink;
@@ -28,8 +29,13 @@ import org.chromium.weblayer_private.aidl.INavigationControllerClient;
 import org.chromium.weblayer_private.aidl.IObjectWrapper;
 import org.chromium.weblayer_private.aidl.ObjectWrapper;
 
+/**
+ * Implementation of IBrowserController.
+ */
 @JNINamespace("weblayer")
-public final class BrowserControllerImpl extends IBrowserController.Stub {
+public final class BrowserControllerImpl extends IBrowserController.Stub
+        implements TopControlsContainerView.Listener,
+                   WebContentsGestureStateTracker.OnGestureStateChangedListener {
     private long mNativeBrowserController;
 
     // TODO: move mContentViewRenderView, mContentView, mTopControlsContainerView to
@@ -46,6 +52,13 @@ public final class BrowserControllerImpl extends IBrowserController.Stub {
     private NavigationControllerImpl mNavigationController;
     private DownloadDelegateProxy mDownloadDelegateProxy;
     private FullscreenDelegateProxy mFullscreenDelegateProxy;
+    private WebContentsGestureStateTracker mGestureStateTracker;
+    /**
+     * The value of mCachedDoBrowserControlsShrinkRendererSize is set when
+     * WebContentsGestureStateTracker begins a gesture. This is necessary as the values should only
+     * change once a gesture is no longer under way.
+     */
+    private boolean mCachedDoBrowserControlsShrinkRendererSize;
 
     private static class InternalAccessDelegateImpl
             implements ViewEventSink.InternalAccessDelegate {
@@ -77,12 +90,12 @@ public final class BrowserControllerImpl extends IBrowserController.Stub {
         mContentViewRenderView.onNativeLibraryLoaded(
                 windowAndroid, ContentViewRenderView.MODE_SURFACE_VIEW);
 
-        mNativeBrowserController =
-                BrowserControllerImplJni.get().createBrowserController(profile.getNativeProfile());
+        mNativeBrowserController = BrowserControllerImplJni.get().createBrowserController(
+                profile.getNativeProfile(), this);
         mWebContents = BrowserControllerImplJni.get().getWebContents(
                 mNativeBrowserController, BrowserControllerImpl.this);
         mTopControlsContainerView =
-                new TopControlsContainerView(context, mWebContents, mContentViewRenderView);
+                new TopControlsContainerView(context, mWebContents, mContentViewRenderView, this);
         mContentView = ContentView.createContentView(
                 context, mWebContents, mTopControlsContainerView.getEventOffsetHandler());
         ViewAndroidDelegate viewAndroidDelegate = new ViewAndroidDelegate(mContentView) {
@@ -109,6 +122,8 @@ public final class BrowserControllerImpl extends IBrowserController.Stub {
 
         mWebContents.onShow();
         mContentView.requestFocus();
+
+        mGestureStateTracker = new WebContentsGestureStateTracker(mContentView, mWebContents, this);
     }
 
     long getNativeBrowserController() {
@@ -123,6 +138,29 @@ public final class BrowserControllerImpl extends IBrowserController.Stub {
         return mNavigationController;
     }
 
+    @Override
+    public void onTopControlsCompletelyShownOrHidden() {
+        adjustWebContentsHeightIfNecessary();
+    }
+
+    @Override
+    public void onGestureStateChanged() {
+        if (mGestureStateTracker.isInGestureOrScroll()) {
+            mCachedDoBrowserControlsShrinkRendererSize =
+                    mTopControlsContainerView.isTopControlVisible();
+        }
+        adjustWebContentsHeightIfNecessary();
+    }
+
+    private void adjustWebContentsHeightIfNecessary() {
+        if (mGestureStateTracker.isInGestureOrScroll()
+                || !mTopControlsContainerView.isTopControlsCompletelyShownOrHidden()) {
+            return;
+        }
+        mContentViewRenderView.setWebContentsHeightDelta(
+                mTopControlsContainerView.getTopContentOffset());
+    }
+
     @Override
     public void setClient(IBrowserControllerClient client) {
         mBrowserObserverProxy = new BrowserObserverProxy(mNativeBrowserController, client);
@@ -191,6 +229,7 @@ public final class BrowserControllerImpl extends IBrowserController.Stub {
             mFullscreenDelegateProxy.destroy();
             mFullscreenDelegateProxy = null;
         }
+        mGestureStateTracker.destroy();
         mNavigationController = null;
         BrowserControllerImplJni.get().deleteBrowserController(mNativeBrowserController);
         mNativeBrowserController = 0;
@@ -212,9 +251,16 @@ public final class BrowserControllerImpl extends IBrowserController.Stub {
                 (ValueCallback<Boolean>) ObjectWrapper.unwrap(callback, ValueCallback.class));
     }
 
+    @CalledByNative
+    private boolean doBrowserControlsShrinkRendererSize() {
+        return (mGestureStateTracker.isInGestureOrScroll())
+                ? mCachedDoBrowserControlsShrinkRendererSize
+                : mTopControlsContainerView.isTopControlVisible();
+    }
+
     @NativeMethods
     interface Natives {
-        long createBrowserController(long profile);
+        long createBrowserController(long profile, BrowserControllerImpl caller);
         void setTopControlsContainerView(long nativeBrowserControllerImpl,
                 BrowserControllerImpl caller, long nativeTopControlsContainerView);
         void deleteBrowserController(long browserController);

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

@@ -62,6 +62,8 @@ public class ContentViewRenderView extends FrameLayout {
     private int mWidth;
     private int mHeight;
 
+    private int mWebContentsHeightDelta;
+
     // Common interface to listen to surface related events.
     private interface SurfaceEventListener {
         void surfaceCreated();
@@ -514,11 +516,25 @@ public class ContentViewRenderView extends FrameLayout {
         mRequested.addCallback(callback);
     }
 
+    /**
+     * Sets how much to decrease the height of the WebContents by.
+     */
+    public void setWebContentsHeightDelta(int delta) {
+        if (delta == mWebContentsHeightDelta) return;
+        mWebContentsHeightDelta = delta;
+        updateWebContentsSize();
+    }
+
+    private void updateWebContentsSize() {
+        if (mWebContents == null) return;
+        mWebContents.setSize(mWidth, mHeight - mWebContentsHeightDelta);
+    }
+
     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         mWidth = w;
         mHeight = h;
-        if (mWebContents != null) mWebContents.setSize(w, h);
+        updateWebContentsSize();
     }
 
     /**
@@ -581,7 +597,7 @@ public class ContentViewRenderView extends FrameLayout {
         mWebContents = webContents;
 
         if (webContents != null) {
-            webContents.setSize(mWidth, mHeight);
+            updateWebContentsSize();
             ContentViewRenderViewJni.get().onPhysicalBackingSizeChanged(
                     mNativeContentViewRenderView, webContents, mWidth, mHeight);
         }

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

@@ -26,6 +26,30 @@ import org.chromium.ui.resources.dynamics.ViewResourceAdapter;
  * bitmap is placed in a cc::Layer and the layer is shown while scrolling the top-view.
  * ViewResourceAdapter is always kept in sync, as to do otherwise results in a noticeable delay
  * between when the scroll starts the content is available.
+ *
+ * There are many parts involved in orchestrating top-controls scrolling. The key things to know
+ * are:
+ * . TopControlsContainerView (in native code) keeps a cc::Layer that shows a bitmap rendered by
+ *   the top-view. The bitmap is updated anytime the top-view changes. This is done as otherwise
+ *   there is a noticable delay between when the scroll starts and the bitmap is available.
+ * . When scrolling, the cc::Layer for the WebContents and TopControlsContainerView is moved.
+ * . The size of the WebContents is only changed after the user releases a touch point. Otherwise
+ *   the scrollbar bounces around.
+ * . WebContentsDelegate::DoBrowserControlsShrinkRendererSize() only changes when the WebContents
+ *   size change.
+ * . WebContentsGestureStateTracker is responsible for determining when a scroll/touch is underway.
+ * . ContentViewRenderView.Delegate is used to adjust the size of the webcontents when the
+ *   top-controls are fully visible (and a scroll is not underway).
+ *
+ * The flow of this code is roughly:
+ * . WebContentsGestureStateTracker generally detects a touch first
+ * . BrowserControllerImpl is notified and caches state.
+ * . onTopControlsChanged() is called. This triggers hiding the real view and calling to native code
+ *   to move the cc::Layers.
+ * . the move continues.
+ * . when the move completes and both WebContentsGestureStateTracker and TopControlsContainerView
+ *   no longer believe a move/gesture/scroll is underway the size of the WebContents is adjusted
+ *   (if necessary).
  */
 @JNINamespace("weblayer")
 class TopControlsContainerView extends FrameLayout {
@@ -50,7 +74,9 @@ class TopControlsContainerView extends FrameLayout {
     private EventOffsetHandler mEventOffsetHandler;
     private int mTopContentOffset;
 
-    // True if scrolling.
+    // Set to true if |mView| is hidden because the user has scrolled or triggered some action such
+    // that mView is not visible. While |mView| is not visible if this is true, the bitmap from
+    // |mView| may be partially visible.
     private boolean mInTopControlsScroll;
 
     private boolean mIsFullscreen;
@@ -58,6 +84,15 @@ class TopControlsContainerView extends FrameLayout {
     // Used to delay processing fullscreen requests.
     private Runnable mSystemUiFullscreenResizeRunnable;
 
+    private final Listener mListener;
+
+    public interface Listener {
+        /**
+         * Called when the top-controls are either completely showing, or completely hiding.
+         */
+        public void onTopControlsCompletelyShownOrHidden();
+    }
+
     // Used to  delay updating the image for the layer.
     private final Runnable mRefreshResourceIdRunnable = () -> {
         if (mView == null) return;
@@ -65,8 +100,8 @@ class TopControlsContainerView extends FrameLayout {
                 mNativeTopControlsContainerView, TopControlsContainerView.this);
     };
 
-    TopControlsContainerView(
-            Context context, WebContents webContents, ContentViewRenderView contentViewRenderView) {
+    TopControlsContainerView(Context context, WebContents webContents,
+            ContentViewRenderView contentViewRenderView, Listener listener) {
         super(context);
         mContentViewRenderView = contentViewRenderView;
         mWebContents = webContents;
@@ -85,6 +120,7 @@ class TopControlsContainerView extends FrameLayout {
         mNativeTopControlsContainerView =
                 TopControlsContainerViewJni.get().createTopControlsContainerView(
                         this, webContents, contentViewRenderView.getNativeHandle());
+        mListener = listener;
     }
 
     public void destroy() {
@@ -101,6 +137,21 @@ class TopControlsContainerView extends FrameLayout {
         return mEventOffsetHandler;
     }
 
+    /**
+     * Returns the vertical offset for the WebContents.
+     */
+    public int getTopContentOffset() {
+        return mView == null ? 0 : mTopContentOffset;
+    }
+
+    /**
+     * Returns true if the top control is visible to the user.
+     */
+    public boolean isTopControlVisible() {
+        // Don't check the visibility of the View itself as it's hidden while scrolling.
+        return mView != null && mTopContentOffset != 0;
+    }
+
     /**
      * Sets the view from the client.
      */
@@ -216,8 +267,19 @@ class TopControlsContainerView extends FrameLayout {
         mContentViewRenderView.postOnAnimation(() -> showTopControls());
     }
 
+    /**
+     * Returns true if the top-controls are completely shown or completely hidden. A return value
+     * of false indicates the top-controls are being moved.
+     */
+    public boolean isTopControlsCompletelyShownOrHidden() {
+        return mTopContentOffset == 0 || mTopContentOffset == getHeight();
+    }
+
     private void setTopControlsOffset(int topControlsOffsetY, int topContentOffsetY) {
         mTopContentOffset = topContentOffsetY;
+        if (isTopControlsCompletelyShownOrHidden()) {
+            mListener.onTopControlsCompletelyShownOrHidden();
+        }
         TopControlsContainerViewJni.get().setTopControlsOffset(mNativeTopControlsContainerView,
                 TopControlsContainerView.this, topControlsOffsetY, topContentOffsetY);
     }

weblayer/browser/java/org/chromium/weblayer_private/WebContentsGestureStateTracker.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 android.view.MotionEvent;
+import android.view.View;
+
+import org.chromium.content_public.browser.GestureListenerManager;
+import org.chromium.content_public.browser.GestureStateListener;
+import org.chromium.content_public.browser.WebContents;
+
+/**
+ * WebContentsGestureStateTracker is responsible for tracking when a scroll/gesture is in progress
+ * and notifying when the state changes.
+ */
+// TODO(sky): refactor TabGestureStateListener and this to a common place.
+public final class WebContentsGestureStateTracker {
+    private GestureListenerManager mGestureListenerManager;
+    private GestureStateListener mGestureListener;
+    private final OnGestureStateChangedListener mListener;
+    private boolean mScrolling;
+    private boolean mIsInGesture;
+
+    /**
+     * The View events are tracked on.
+     */
+    private View mContentView;
+
+    /**
+     * Notified when the gesture state changes.
+     */
+    public interface OnGestureStateChangedListener {
+        /**
+         * Called when the value of isInGestureOrScroll() changes.
+         */
+        public void onGestureStateChanged();
+    }
+
+    public WebContentsGestureStateTracker(
+            View contentView, WebContents webContents, OnGestureStateChangedListener listener) {
+        mListener = listener;
+        mGestureListenerManager = GestureListenerManager.fromWebContents(webContents);
+        mContentView = contentView;
+        mContentView.setOnTouchListener(new View.OnTouchListener() {
+            @Override
+            public boolean onTouch(View view, MotionEvent event) {
+                final int eventAction = event.getActionMasked();
+                final boolean oldState = isInGestureOrScroll();
+                if (eventAction == MotionEvent.ACTION_DOWN
+                        || eventAction == MotionEvent.ACTION_POINTER_DOWN) {
+                    mIsInGesture = true;
+                } else if (eventAction == MotionEvent.ACTION_CANCEL
+                        || eventAction == MotionEvent.ACTION_UP) {
+                    mIsInGesture = false;
+                }
+                if (isInGestureOrScroll() != oldState) {
+                    mListener.onGestureStateChanged();
+                }
+                return false;
+            }
+        });
+
+        mGestureListener = new GestureStateListener() {
+            @Override
+            public void onFlingStartGesture(int scrollOffsetY, int scrollExtentY) {
+                onScrollingStateChanged();
+            }
+
+            @Override
+            public void onFlingEndGesture(int scrollOffsetY, int scrollExtentY) {
+                onScrollingStateChanged();
+            }
+
+            @Override
+            public void onScrollStarted(int scrollOffsetY, int scrollExtentY) {
+                onScrollingStateChanged();
+            }
+
+            @Override
+            public void onScrollEnded(int scrollOffsetY, int scrollExtentY) {
+                onScrollingStateChanged();
+            }
+
+            private void onScrollingStateChanged() {
+                final boolean oldState = isInGestureOrScroll();
+                mScrolling = mGestureListenerManager.isScrollInProgress();
+                if (oldState != isInGestureOrScroll()) {
+                    mListener.onGestureStateChanged();
+                }
+            }
+        };
+        mGestureListenerManager.addListener(mGestureListener);
+    }
+
+    public void destroy() {
+        mGestureListenerManager.removeListener(mGestureListener);
+        mGestureListener = null;
+        mGestureListenerManager = null;
+        mContentView.setOnTouchListener(null);
+    }
+
+    /**
+     * Returns true if the user has touched the target view, or is scrolling.
+     */
+    public boolean isInGestureOrScroll() {
+        return mIsInGesture || mScrolling;
+    }
+}