Mac: Share kScrollbarPixelsPerCocoaTick between ui:: and blink:: events

content/browser/renderer_host/input/web_input_event_builders_mac_unittest.mm

Index: content/browser/renderer_host/input/web_input_event_builders_mac_unittest.mm
diff --git a/content/browser/renderer_host/input/web_input_event_builders_mac_unittest.mm b/content/browser/renderer_host/input/web_input_event_builders_mac_unittest.mm
index 9b6500a27a5d56df3c4f1d98fc6a1b183f573ea2..45e92129e8a066ffc8f640e5fa391f228e782ae6 100644
--- a/content/browser/renderer_host/input/web_input_event_builders_mac_unittest.mm
+++ b/content/browser/renderer_host/input/web_input_event_builders_mac_unittest.mm
@@ -10,9 +10,12 @@
 
 #include "base/macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#import "ui/events/cocoa/cocoa_event_utils.h"
+#include "ui/events/event.h"
 #include "ui/events/keycodes/dom/dom_code.h"
 #include "ui/events/keycodes/dom/dom_key.h"
 #include "ui/events/keycodes/keyboard_codes.h"
+#import "ui/events/test/cocoa_test_event_utils.h"
 
 using blink::WebKeyboardEvent;
 using blink::WebInputEvent;
@@ -559,3 +562,41 @@ TEST(WebInputEventBuilderMacTest, DomKeyFlagsChanged) {
     EXPECT_EQ(entry.dom_key, web_event.domKey) << entry.mac_key_code;
   }
 }
+
+// Test that a ui::Event and blink::WebInputEvent made from the same NSEvent
+// have the same values for comparable fields.
+TEST(WebInputEventBuilderMacTest, ScrollWheelMatchesUIEvent) {
+  CGFloat delta_x = 123;
+  CGFloat delta_y = 321;
+  NSPoint location = NSMakePoint(11, 22);
+
+  // WebMouseWheelEventBuilder requires a non-nil view to map coordinates. So
+  // create a dummy window, but don't show it. It will be released when closed.
+  NSWindow* window =
+      [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 100, 100)
+                                  styleMask:NSBorderlessWindowMask
+                                    backing:NSBackingStoreBuffered
+                                      defer:NO];
+
+  NSEvent* mac_event = cocoa_test_event_utils::TestScrollEvent(
+      location, window, delta_x, delta_y);
+
+  blink::WebMouseWheelEvent web_event =
+      content::WebMouseWheelEventBuilder::Build(mac_event,
+                                                [window contentView]);
+  ui::MouseWheelEvent ui_event(mac_event);
+
+  EXPECT_EQ(delta_x * ui::kScrollbarPixelsPerCocoaTick, web_event.deltaX);
+  EXPECT_EQ(web_event.deltaX, ui_event.x_offset());
+
+  EXPECT_EQ(delta_y * ui::kScrollbarPixelsPerCocoaTick, web_event.deltaY);
+  EXPECT_EQ(web_event.deltaY, ui_event.y_offset());
+
+  EXPECT_EQ(11, web_event.x);
+  EXPECT_EQ(web_event.x, ui_event.x());
+
+  // Both ui:: and blink:: events use an origin at the top-left.
+  EXPECT_EQ(100 - 22, web_event.y);
+  EXPECT_EQ(web_event.y, ui_event.y());
+  [window close];
+}