Update WebInputEventFactory on Mac for pinch gesture support

WebInputEventFactory::gestureEvent was added a long time ago but is
not currently used.  Remove the existing unused code and update the
function to support creating GesturePinchUpdate events from Cocoa
NSEventTypeMagnify events.

BUG=289887

Review URL: https://codereview.chromium.org/184983003

git-svn-id: svn://svn.chromium.org/blink/trunk@168482 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/web/WebInputEventFactoryMac.mm

@@ -366,19 +366,6 @@ static int windowsKeyCodeForKeyEvent(NSEvent* event)
     return windowsKeyCodeForKeyCode([event keyCode]);
 }
 
-static WebInputEvent::Type gestureEventTypeForEvent(NSEvent *event)
-{
-    switch ([event type]) {
-    case NSEventTypeBeginGesture:
-        return WebInputEvent::GestureScrollBegin;
-    case NSEventTypeEndGesture:
-        return WebInputEvent::GestureScrollEnd;
-    default:
-        ASSERT_NOT_REACHED();
-        return WebInputEvent::GestureScrollEnd;
-    }
-}
-
 static inline NSString* textFromEvent(NSEvent* event)
 {
     if ([event type] == NSFlagsChanged)
@@ -1138,10 +1125,21 @@ WebGestureEvent WebInputEventFactory::gestureEvent(NSEvent *event, NSView *view)
     result.globalX = temp.globalX;
     result.globalY = temp.globalY;
 
-    result.type = gestureEventTypeForEvent(event);
     result.modifiers = modifiersFromEvent(event);
     result.timeStampSeconds = [event timestamp];
 
+    // MacOS X gestures are used only for pinch support.
+    result.sourceDevice = WebGestureEvent::Touchpad;
+    switch ([event type]) {
+    case NSEventTypeMagnify:
+        result.type = WebInputEvent::GesturePinchUpdate;
+        result.data.pinchUpdate.scale = [event magnification];
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+        result.type = WebInputEvent::Undefined;
+    }
+
     return result;
 }