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 8acbe0e04d4a362ba4ce1fa906775ee20a1295cd..bce32c96e0267d96e370a0f2fcdd5fec39d90ed1 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 +288,7 @@ 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);
+    wheel_delta = static_cast<float>(GET_WHEEL_DELTA_WPARAM(wparam));

[Rick Byers, 2016/01/12 14:12:21]

nit: maybe worth a comment saying that we err on the side of
hasPreciseScrollingDeltas=false because we don't see any way to know for sure on
Windows.

[skobes, 2016/01/14 22:36:07]

Done.

 
     if (message == WM_MOUSEHWHEEL) {
       horizontal_scroll = true;