Add CRWWebViewScrollViewProxy.decelerating

ios/web/web_state/ui/crw_web_view_scroll_view_proxy_unittest.mm

Index: ios/web/web_state/ui/crw_web_view_scroll_view_proxy_unittest.mm
diff --git a/ios/web/web_state/ui/crw_web_view_scroll_view_proxy_unittest.mm b/ios/web/web_state/ui/crw_web_view_scroll_view_proxy_unittest.mm
index f1c17ddd0eba61a293c0936db6f4d0e1fd21da3c..f5dee07164824b506989673afe8b3c37fe577d81 100644
--- a/ios/web/web_state/ui/crw_web_view_scroll_view_proxy_unittest.mm
+++ b/ios/web/web_state/ui/crw_web_view_scroll_view_proxy_unittest.mm
@@ -102,6 +102,12 @@ TEST_F(CRWWebViewScrollViewProxyTest, testScrollViewPresent) {
       frame];
   EXPECT_TRUE(CGRectEqualToRect(frame, [webViewScrollViewProxy_ frame]));
 
+  [[[mockScrollView_ expect] andReturnValue:@YES] isDecelerating];
+  EXPECT_TRUE([webViewScrollViewProxy_ isDecelerating]);
+
+  [[[mockScrollView_ expect] andReturnValue:@NO] isDecelerating];
+  EXPECT_FALSE([webViewScrollViewProxy_ isDecelerating]);
+
   [[[mockScrollView_ expect] andReturnValue:@YES] isDragging];
   EXPECT_TRUE([webViewScrollViewProxy_ isDragging]);
 
@@ -123,6 +129,7 @@ TEST_F(CRWWebViewScrollViewProxyTest, testScrollViewAbsent) {
   EXPECT_TRUE(
       CGSizeEqualToSize(CGSizeZero, [webViewScrollViewProxy_ contentSize]));
   EXPECT_TRUE(CGRectEqualToRect(CGRectZero, [webViewScrollViewProxy_ frame]));
+  EXPECT_FALSE([webViewScrollViewProxy_ isDecelerating]);
   EXPECT_FALSE([webViewScrollViewProxy_ isDragging]);
 
   // Make sure setting the properties is fine too.