[WebView] Enable scrolling in fullscreen.

The next step is to fix crbug/423381 to improve
transitions from/to fullscreen after scrolling.

BUG=398485

Review URL: https://codereview.chromium.org/653633005

Cr-Commit-Position: refs/heads/master@{#300520}

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

@@ -1288,11 +1288,7 @@ public class AwContents {
      * @see View#onScrollChanged(int,int)
      */
     public void onContainerViewScrollChanged(int l, int t, int oldl, int oldt) {
-        // A side-effect of View.onScrollChanged is that the scroll accessibility event being sent
-        // by the base class implementation. This is completely hidden from the base classes and
-        // cannot be prevented, which is why we need the code below.
-        mScrollAccessibilityHelper.removePostedViewScrolledAccessibilityEventCallback();
-        mScrollOffsetManager.onContainerViewScrollChanged(l, t);
+        mAwViewMethods.onContainerViewScrollChanged(l, t, oldl, oldt);
     }
 
     /**
@@ -1301,17 +1297,7 @@ public class AwContents {
      */
     public void onContainerViewOverScrolled(int scrollX, int scrollY, boolean clampedX,
             boolean clampedY) {
-        int oldX = mContainerView.getScrollX();
-        int oldY = mContainerView.getScrollY();
-
-        mScrollOffsetManager.onContainerViewOverScrolled(scrollX, scrollY, clampedX, clampedY);
-
-        if (mOverScrollGlow != null) {
-            mOverScrollGlow.pullGlow(mContainerView.getScrollX(), mContainerView.getScrollY(),
-                    oldX, oldY,
-                    mScrollOffsetManager.computeMaximumHorizontalScrollOffset(),
-                    mScrollOffsetManager.computeMaximumVerticalScrollOffset());
-        }
+        mAwViewMethods.onContainerViewOverScrolled(scrollX, scrollY, clampedX, clampedY);
     }
 
     /**
@@ -1323,46 +1309,46 @@ public class AwContents {
                 rect, immediate);
     }
 
-    /**
-     * @see View.computeScroll()
-     */
-    public void computeScroll() {
-        mScrollOffsetManager.computeScrollAndAbsorbGlow(mOverScrollGlow);
-    }
-
     /**
      * @see View#computeHorizontalScrollRange()
      */
     public int computeHorizontalScrollRange() {
-        return mScrollOffsetManager.computeHorizontalScrollRange();
+        return mAwViewMethods.computeHorizontalScrollRange();
     }
 
     /**
      * @see View#computeHorizontalScrollOffset()
      */
     public int computeHorizontalScrollOffset() {
-        return mScrollOffsetManager.computeHorizontalScrollOffset();
+        return mAwViewMethods.computeHorizontalScrollOffset();
     }
 
     /**
      * @see View#computeVerticalScrollRange()
      */
     public int computeVerticalScrollRange() {
-        return mScrollOffsetManager.computeVerticalScrollRange();
+        return mAwViewMethods.computeVerticalScrollRange();
     }
 
     /**
      * @see View#computeVerticalScrollOffset()
      */
     public int computeVerticalScrollOffset() {
-        return mScrollOffsetManager.computeVerticalScrollOffset();
+        return mAwViewMethods.computeVerticalScrollOffset();
     }
 
     /**
      * @see View#computeVerticalScrollExtent()
      */
     public int computeVerticalScrollExtent() {
-        return mScrollOffsetManager.computeVerticalScrollExtent();
+        return mAwViewMethods.computeVerticalScrollExtent();
+    }
+
+    /**
+     * @see View.computeScroll()
+     */
+    public void computeScroll() {
+        mAwViewMethods.computeScroll();
     }
 
     /**
@@ -2476,6 +2462,61 @@ public class AwContents {
             if (mIsWindowVisible == windowVisible) return;
             setWindowVisibilityInternal(windowVisible);
         }
+
+        @Override
+        public void onContainerViewScrollChanged(int l, int t, int oldl, int oldt) {
+            // A side-effect of View.onScrollChanged is that the scroll accessibility event being
+            // sent by the base class implementation. This is completely hidden from the base
+            // classes and cannot be prevented, which is why we need the code below.
+            mScrollAccessibilityHelper.removePostedViewScrolledAccessibilityEventCallback();
+            mScrollOffsetManager.onContainerViewScrollChanged(l, t);
+        }
+
+        @Override
+        public void onContainerViewOverScrolled(int scrollX, int scrollY, boolean clampedX,
+                boolean clampedY) {
+            int oldX = mContainerView.getScrollX();
+            int oldY = mContainerView.getScrollY();
+
+            mScrollOffsetManager.onContainerViewOverScrolled(scrollX, scrollY, clampedX, clampedY);
+
+            if (mOverScrollGlow != null) {
+                mOverScrollGlow.pullGlow(mContainerView.getScrollX(), mContainerView.getScrollY(),
+                        oldX, oldY,
+                        mScrollOffsetManager.computeMaximumHorizontalScrollOffset(),
+                        mScrollOffsetManager.computeMaximumVerticalScrollOffset());
+            }
+        }
+
+        @Override
+        public int computeHorizontalScrollRange() {
+            return mScrollOffsetManager.computeHorizontalScrollRange();
+        }
+
+        @Override
+        public int computeHorizontalScrollOffset() {
+            return mScrollOffsetManager.computeHorizontalScrollOffset();
+        }
+
+        @Override
+        public int computeVerticalScrollRange() {
+            return mScrollOffsetManager.computeVerticalScrollRange();
+        }
+
+        @Override
+        public int computeVerticalScrollOffset() {
+            return mScrollOffsetManager.computeVerticalScrollOffset();
+        }
+
+        @Override
+        public int computeVerticalScrollExtent() {
+            return mScrollOffsetManager.computeVerticalScrollExtent();
+        }
+
+        @Override
+        public void computeScroll() {
+            mScrollOffsetManager.computeScrollAndAbsorbGlow(mOverScrollGlow);
+        }
     }
 
     // Return true if the GeolocationPermissionAPI should be used.

android_webview/java/src/org/chromium/android_webview/AwViewMethods.java

@@ -112,4 +112,45 @@ interface AwViewMethods {
      * @see android.view.View#onWindowVisibilityChanged
      */
     void onWindowVisibilityChanged(int visibility);
+
+    /**
+     * @see android.view.View#onScrollChanged
+     */
+    void onContainerViewScrollChanged(int l, int t, int oldl, int oldt);
+
+    /**
+     * @see android.view.View#onOverScrolled
+     */
+    void onContainerViewOverScrolled(
+            int scrollX, int scrollY, boolean clampedX, boolean clampedY);
+
+    /**
+     * @see android.view.View#computeHorizontalScrollRange
+     */
+    int computeHorizontalScrollRange();
+
+    /**
+     * @see android.view.View#computeHorizontalScrollOffset
+     */
+    int computeHorizontalScrollOffset();
+
+    /**
+     * @see android.view.View#computeVerticalScrollRange
+     */
+    int computeVerticalScrollRange();
+
+    /**
+     * @see android.view.View#computeVerticalScrollOffset
+     */
+    int computeVerticalScrollOffset();
+
+    /**
+     * @see android.view.View#computeVerticalScrollExtent
+     */
+    int computeVerticalScrollExtent();
+
+    /**
+     * @see android.view.View#computeScroll
+     */
+    void computeScroll();
 }

android_webview/java/src/org/chromium/android_webview/FullScreenView.java

@@ -140,6 +140,47 @@ public class FullScreenView extends FrameLayout {
         mAwViewMethods.onWindowVisibilityChanged(visibility);
     }
 
+    @Override
+    public void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) {
+        mAwViewMethods.onContainerViewOverScrolled(scrollX, scrollY, clampedX, clampedY);
+    }
+
+    @Override
+    public void onScrollChanged(int l, int t, int oldl, int oldt) {
+        super.onScrollChanged(l, t, oldl, oldt);
+        mAwViewMethods.onContainerViewScrollChanged(l, t, oldl, oldt);
+    }
+
+    @Override
+    public int computeHorizontalScrollRange() {
+        return mAwViewMethods.computeHorizontalScrollRange();
+    }
+
+    @Override
+    public int computeHorizontalScrollOffset() {
+        return mAwViewMethods.computeHorizontalScrollOffset();
+    }
+
+    @Override
+    public int computeVerticalScrollRange() {
+        return mAwViewMethods.computeVerticalScrollRange();
+    }
+
+    @Override
+    public int computeVerticalScrollOffset() {
+        return mAwViewMethods.computeVerticalScrollOffset();
+    }
+
+    @Override
+    public int computeVerticalScrollExtent() {
+        return mAwViewMethods.computeVerticalScrollExtent();
+    }
+
+    @Override
+    public void computeScroll() {
+        mAwViewMethods.computeScroll();
+    }
+
     // AwContents.InternalAccessDelegate implementation --------------------------------------
     private class InternalAccessAdapter implements AwContents.InternalAccessDelegate {
 
@@ -181,29 +222,30 @@ public class FullScreenView extends FrameLayout {
 
         @Override
         public boolean awakenScrollBars() {
-            return false;
+            return FullScreenView.this.awakenScrollBars(0);
         }
 
         @Override
         public boolean super_awakenScrollBars(int startDelay, boolean invalidate) {
-            return false;
+            return FullScreenView.super.awakenScrollBars(startDelay, invalidate);
         }
 
         @Override
         public void onScrollChanged(int lPix, int tPix, int oldlPix, int oldtPix) {
-            // Intentional no-op.
+            FullScreenView.this.onScrollChanged(lPix, tPix, oldlPix, oldtPix);
         }
 
         @Override
         public void overScrollBy(int deltaX, int deltaY, int scrollX, int scrollY,
                 int scrollRangeX, int scrollRangeY, int maxOverScrollX,
                 int maxOverScrollY, boolean isTouchEvent) {
-            // Intentional no-op.
+            FullScreenView.this.overScrollBy(deltaX, deltaY, scrollX, scrollY, scrollRangeX,
+                    scrollRangeY, maxOverScrollX, maxOverScrollY, isTouchEvent);
         }
 
         @Override
         public void super_scrollTo(int scrollX, int scrollY) {
-            // Intentional no-op.
+            FullScreenView.super.scrollTo(scrollX, scrollY);
         }
 
         @Override

android_webview/java/src/org/chromium/android_webview/NullAwViewMethods.java

@@ -127,4 +127,45 @@ class NullAwViewMethods implements AwViewMethods {
     public void onWindowVisibilityChanged(int visibility) {
         // Intentional no-op.
     }
+
+    @Override
+    public void onContainerViewScrollChanged(int l, int t, int oldl, int oldt) {
+        // Intentional no-op.
+    }
+
+    @Override
+    public void onContainerViewOverScrolled(int scrollX, int scrollY, boolean clampedX,
+            boolean clampedY) {
+        // Intentional no-op.
+    }
+
+    @Override
+    public int computeHorizontalScrollRange() {
+        return 0;
+    }
+
+    @Override
+    public int computeHorizontalScrollOffset() {
+        return 0;
+    }
+
+    @Override
+    public int computeVerticalScrollRange() {
+        return 0;
+    }
+
+    @Override
+    public int computeVerticalScrollOffset() {
+        return 0;
+    }
+
+    @Override
+    public int computeVerticalScrollExtent() {
+        return 0;
+    }
+
+    @Override
+    public void computeScroll() {
+        // Intentional no-op.
+    }
 }