Revert of Explicitly suppress scrolling for wheel events that will trigger zooming

content/renderer/input/input_handler_proxy.cc

Index: content/renderer/input/input_handler_proxy.cc
diff --git a/content/renderer/input/input_handler_proxy.cc b/content/renderer/input/input_handler_proxy.cc
index 602f1130c5cdbcf546978dbece568e73d1a979f9..3edb957ab77b200c066f2485617198dca2f0565b 100644
--- a/content/renderer/input/input_handler_proxy.cc
+++ b/content/renderer/input/input_handler_proxy.cc
@@ -324,9 +324,9 @@
     // TODO(jamesr): We don't properly handle scroll by page in the compositor
     // thread, so punt it to the main thread. http://crbug.com/236639
     result = DID_NOT_HANDLE;
-  } else if (!wheel_event.canScroll) {
-    // Wheel events with |canScroll| == false will not trigger scrolling,
-    // only event handlers.  Forward to the main thread.
+  } else if (wheel_event.modifiers & WebInputEvent::ControlKey) {
+    // Wheel events involving the control key never trigger scrolling, only
+    // event handlers.  Forward to the main thread.
     result = DID_NOT_HANDLE;
   } else if (smooth_scroll_enabled_) {
     cc::InputHandler::ScrollStatus scroll_status =