Remove the % WHEEL_DELTA check in WebMouseWheelEventBuilder.

content/browser/renderer_host/input/web_input_event_builders_win.cc

Index: content/browser/renderer_host/input/web_input_event_builders_win.cc
diff --git a/content/browser/renderer_host/input/web_input_event_builders_win.cc b/content/browser/renderer_host/input/web_input_event_builders_win.cc
index 0b964e231e7b1000e075cfcf017b1d0c426dea75..33701fb1ab2e8fa70efcdba0cf28122d66912870 100644
--- a/content/browser/renderer_host/input/web_input_event_builders_win.cc
+++ b/content/browser/renderer_host/input/web_input_event_builders_win.cc
@@ -288,15 +288,10 @@ WebMouseWheelEvent WebMouseWheelEventBuilder::Build(HWND hwnd,
     result.globalX = static_cast<short>(LOWORD(lparam));
     result.globalY = static_cast<short>(HIWORD(lparam));
 
-    short wheel_delta_wparam = GET_WHEEL_DELTA_WPARAM(wparam);
-    // The current heuristic for setting hasPreciseScrollingDelta is whether or
-    // not wheel_delta is an exact multiple of WHEEL_DELTA. Note that high
-    // precision trackpads can occasionally generate deltas that are an exact
-    // multiple of WHEEL_DELTA.
-    if (wheel_delta_wparam % WHEEL_DELTA != 0)
-      result.hasPreciseScrollingDeltas = true;
-
-    wheel_delta = static_cast<float>(wheel_delta_wparam);
+    // Currently we leave hasPreciseScrollingDeltas false, even for trackpad
+    // scrolls that generate WM_MOUSEWHEEL, since we don't have a good way to
+    // distinguish these from real mouse wheels (crbug.com/545234).
+    wheel_delta = static_cast<float>(GET_WHEEL_DELTA_WPARAM(wparam));
 
     if (message == WM_MOUSEHWHEEL) {
       horizontal_scroll = true;