Explicitly suppress scrolling for wheel events that will trigger zooming

content/common/input/web_input_event_traits_unittest.cc

Index: content/common/input/web_input_event_traits_unittest.cc
diff --git a/content/common/input/web_input_event_traits_unittest.cc b/content/common/input/web_input_event_traits_unittest.cc
index 7a7cb7ff8b3e878eec275c8445494fbb8a6aefa4..98a7a2b1ec03df4821a554cb0737220b940f0ca8 100644
--- a/content/common/input/web_input_event_traits_unittest.cc
+++ b/content/common/input/web_input_event_traits_unittest.cc
@@ -51,6 +51,14 @@ class WebInputEventTraitsTest : public testing::Test {
     event.y = y;
     return event;
   }
+
+  static WebMouseWheelEvent CreateMouseWheel(WebInputEvent::Type type,

[Rick Byers, 2014/12/12 22:20:29]

no need to take a 'type' here - unlike touch/gesture there's only a single type
of 'wheel' event.

Also kind of weird to take 'canScroll' but nothing else.  Maybe take
deltaX/deltaY since those are the most important parts of a WebMouseWheelEvent?

[lanwei, 2014/12/17 23:16:40]

Done.

+                                             bool canScroll) {
+    WebMouseWheelEvent event;
+    event.type = type;
+    event.canScroll = canScroll;
+    return event;
+  }
 };
 
 TEST_F(WebInputEventTraitsTest, TouchEventCoalescing) {
@@ -162,6 +170,24 @@ TEST_F(WebInputEventTraitsTest, PinchEventCoalescing) {
   EXPECT_EQ(numeric_limits<float>::max(), pinch1.data.pinchUpdate.scale);
 }
 
+TEST_F(WebInputEventTraitsTest, WebMouseWheelEventCoalescing) {
+  WebMouseWheelEvent mouseWheel0 =
+      CreateMouseWheel(WebInputEvent::MouseWheel, true);
+  WebMouseWheelEvent mouseWheel1 =
+      CreateMouseWheel(WebInputEvent::MouseWheel, false);
+
+  // WebMouseWheelEvent objects with different canScroll values should not

[Rick Byers, 2014/12/12 22:20:29]

please add a baseline that verifies CanCoalesce ever returns true in some case -
eg. when everything matches except the deltas.

[lanwei, 2014/12/17 23:16:40]

Done.

+  // coalesce.
+  EXPECT_FALSE(WebInputEventTraits::CanCoalesce(mouseWheel0, mouseWheel1));
+
+  // WebMouseWheelEvent objects with different modifiers should not coalesce.
+  mouseWheel0 = CreateMouseWheel(WebInputEvent::MouseWheel, true);
+  mouseWheel1 = CreateMouseWheel(WebInputEvent::MouseWheel, true);
+  mouseWheel0.modifiers = blink::WebInputEvent::ControlKey;
+  mouseWheel1.modifiers = blink::WebInputEvent::ShiftKey;
+  EXPECT_FALSE(WebInputEventTraits::CanCoalesce(mouseWheel0, mouseWheel1));
+}
+
 // Very basic smoke test to ensure stringification doesn't explode.
 TEST_F(WebInputEventTraitsTest, ToString) {
   WebKeyboardEvent key;