Add more methods to CWVScrollView and CWVScrollViewDelegate.

ios/web_view/internal/cwv_scroll_view.mm

Index: ios/web_view/internal/cwv_scroll_view.mm
diff --git a/ios/web_view/internal/cwv_scroll_view.mm b/ios/web_view/internal/cwv_scroll_view.mm
index 53dc5d8cb22857e8edd9ced179bc94dcc5e9da57..4a4c2a54da834d9fcb7fbe7e31712eef03d027d8 100644
--- a/ios/web_view/internal/cwv_scroll_view.mm
+++ b/ios/web_view/internal/cwv_scroll_view.mm
@@ -42,14 +42,30 @@
   _proxy.contentOffset = contentOffset;
 }
 
+- (UIEdgeInsets)scrollIndicatorInsets {
+  return _proxy.scrollIndicatorInsets;
+}
+
+- (void)setScrollIndicatorInsets:(UIEdgeInsets)scrollIndicatorInsets {
+  _proxy.scrollIndicatorInsets = scrollIndicatorInsets;
+}
+
 - (CGRect)bounds {
   return {_proxy.contentOffset, _proxy.frame.size};
 }
 
+- (BOOL)isDecelerating {
+  return _proxy.decelerating;
+}
+
 - (BOOL)isDragging {
   return _proxy.dragging;
 }
 
+- (UIPanGestureRecognizer*)panGestureRecognizer {
+  return _proxy.panGestureRecognizer;
+}
+
 - (UIEdgeInsets)contentInset {
   return _proxy.contentInset;
 }
@@ -58,10 +74,18 @@
   _proxy.contentInset = contentInset;
 }
 
+- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated {
+  [_proxy setContentOffset:contentOffset animated:animated];
+}
+
 - (void)addGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer {
   [_proxy addGestureRecognizer:gestureRecognizer];
 }
 
+- (void)removeGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer {
+  [_proxy removeGestureRecognizer:gestureRecognizer];
+}
+
 #pragma mark - NSObject
 
 - (void)dealloc {
@@ -108,6 +132,14 @@
   }
 }
 
+- (void)webViewScrollViewWillBeginZooming:
+    (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
+  SEL selector = @selector(scrollViewWillBeginZooming:);
+  if ([_delegate respondsToSelector:selector]) {
+    [_delegate scrollViewWillBeginZooming:self];
+  }
+}
+
 - (void)webViewScrollViewDidResetContentSize:
     (CRWWebViewScrollViewProxy*)webViewScrollViewProxy {
   self.contentSize = _proxy.contentSize;