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

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 44f103c9de3546fd6135e4aff5ef0ce92b1dde67..7151e151eebee9326e8a68b38424373b94d39aa1 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1333,15 +1333,18 @@
 bool WebContentsImpl::HandleWheelEvent(
     const blink::WebMouseWheelEvent& event) {
 #if !defined(OS_MACOSX)
-  // On platforms other than Mac, control+mousewheel may change zoom. On Mac,
-  // this isn't done for two reasons:
+  // On platforms other than Mac, control+mousewheel changes zoom. On Mac, this
+  // isn't done for two reasons:
   //   -the OS already has a gesture to do this through pinch-zoom
   //   -if a user starts an inertial scroll, let's go, and presses control
   //      (i.e. control+tab) then the OS's buffered scroll events will come in
   //      with control key set which isn't what the user wants
-  if (delegate_ && event.wheelTicksY &&
+  if (delegate_ &&
+      event.wheelTicksY &&
       (event.modifiers & blink::WebInputEvent::ControlKey) &&
-      !event.canScroll) {
+      // Avoid adjusting the zoom in response to two-finger-scrolling touchpad
+      // gestures, which are regrettably easy to trigger accidentally.
+      !event.hasPreciseScrollingDeltas) {
     delegate_->ContentsZoomChange(event.wheelTicksY > 0);
     return true;
   }