Extend MouseWheelEvent to support both X and Y scrolls

The patch extends the ui::MouseWheelEvent class to support
X (horizontal) scrolls and updates the corresponding interface
in event_utils.h. It also revises throughout the codebase where
the old method calls were used.

Contributed by sheckylin@chromium.org

BUG=231419
TEST=Tested on device.

Change-Id: I86a7b6b62ec4ac8c296251a2333234170f1cd2e7

Review URL: https://chromiumcodereview.appspot.com/13829007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198086 0039d316-1c4b-4281-b951-d872f2087c98

13 files changed, 60 insertions, 36 deletions

diff --git a/ash/launcher/overflow_bubble.cc b/ash/launcher/overflow_bubble.cc
index 8291c4d..09613ca 100644
--- a/ash/launcher/overflow_bubble.cc
+++ b/ash/launcher/overflow_bubble.cc
@@ -172,10 +172,14 @@ void OverflowBubbleView::ChildPreferredSizeChanged(views::View* child) {
 }
 
 bool OverflowBubbleView::OnMouseWheel(const ui::MouseWheelEvent& event) {
+  // The MouseWheelEvent was changed to support both X and Y offsets
+  // recently, but the behavior of this function was retained to continue
+  // using Y offsets only. Might be good to simply scroll in both
+  // directions as in OverflowBubbleView::OnScrollEvent.
   if (IsHorizontalAlignment())
-    ScrollByXOffset(-event.offset());
+    ScrollByXOffset(-event.y_offset());
   else
-    ScrollByYOffset(-event.offset());
+    ScrollByYOffset(-event.y_offset());
   Layout();
 
   return true;
diff --git a/content/browser/renderer_host/web_input_event_aura.cc b/content/browser/renderer_host/web_input_event_aura.cc
index d7c68a5..e293377 100644
--- a/content/browser/renderer_host/web_input_event_aura.cc
+++ b/content/browser/renderer_host/web_input_event_aura.cc
@@ -253,7 +253,8 @@ WebKit::WebMouseWheelEvent MakeWebMouseWheelEventFromAuraEvent(
   webkit_event.button = WebKit::WebMouseEvent::ButtonNone;
   webkit_event.modifiers = EventFlagsToWebEventModifiers(event->flags());
   webkit_event.timeStampSeconds = event->time_stamp().InSecondsF();
-  webkit_event.deltaY = event->offset();
+  webkit_event.deltaX = event->x_offset();
+  webkit_event.deltaY = event->y_offset();
   webkit_event.wheelTicksY = webkit_event.deltaY / kPixelsPerTick;
 
   return webkit_event;
diff --git a/ui/app_list/views/contents_view.cc b/ui/app_list/views/contents_view.cc
index 6abda38..e256f4b 100644
--- a/ui/app_list/views/contents_view.cc
+++ b/ui/app_list/views/contents_view.cc
@@ -178,9 +178,11 @@ bool ContentsView::OnMouseWheel(const ui::MouseWheelEvent& event) {
   if (show_state_ != SHOW_APPS)
     return false;
 
-  if (abs(event.offset()) > kMinMouseWheelToSwitchPage) {
-    if (!pagination_model_->has_transition())
-      pagination_model_->SelectPageRelative(event.offset() > 0 ? -1 : 1, true);
+  if (abs(event.y_offset()) > kMinMouseWheelToSwitchPage) {
+    if (!pagination_model_->has_transition()) {
+      pagination_model_->SelectPageRelative(
+          event.y_offset() > 0 ? -1 : 1, true);
+    }
     return true;
   }
 
diff --git a/ui/aura/remote_root_window_host_win.cc b/ui/aura/remote_root_window_host_win.cc
index a30b3ed..c477110 100644
--- a/ui/aura/remote_root_window_host_win.cc
+++ b/ui/aura/remote_root_window_host_win.cc
@@ -350,7 +350,7 @@ void RemoteRootWindowHostWin::OnMouseButton(
   mouse_event.set_flags(flags);
 
   if (type == ui::ET_MOUSEWHEEL) {
-    ui::MouseWheelEvent wheel_event(mouse_event, extra);
+    ui::MouseWheelEvent wheel_event(mouse_event, 0, extra);
     delegate_->OnHostMouseEvent(&wheel_event);
   } else {
     mouse_event.SetClickCount(1);
diff --git a/ui/base/cocoa/events_mac.mm b/ui/base/cocoa/events_mac.mm
index ec83f6b..7dd91b6 100644
--- a/ui/base/cocoa/events_mac.mm
+++ b/ui/base/cocoa/events_mac.mm
@@ -151,10 +151,10 @@ bool IsMouseEvent(const base::NativeEvent& native_event) {
          type == ET_MOUSE_EXITED;
 }
 
-int GetMouseWheelOffset(const base::NativeEvent& native_event) {
+gfx::Vector2d GetMouseWheelOffset(const base::NativeEvent& native_event) {
   // TODO(dhollowa): Come back to this once comparisons can be made with other
   // platforms.
-  return [native_event deltaY];
+  return gfx::Vector2d([native_event deltaX], [native_event deltaY]);
 }
 
 int GetTouchId(const base::NativeEvent& native_event) {
diff --git a/ui/base/events/event.cc b/ui/base/events/event.cc
index 4c94464..495ad76 100644
--- a/ui/base/events/event.cc
+++ b/ui/base/events/event.cc
@@ -394,12 +394,14 @@ MouseWheelEvent::MouseWheelEvent(const base::NativeEvent& native_event)
 
 MouseWheelEvent::MouseWheelEvent(const ScrollEvent& scroll_event)
     : MouseEvent(scroll_event),
-      offset_(scroll_event.y_offset()) {
+      offset_(scroll_event.x_offset(), scroll_event.y_offset()){
   SetType(ET_MOUSEWHEEL);
 }
 
-MouseWheelEvent::MouseWheelEvent(const MouseEvent& mouse_event, int offset)
-    : MouseEvent(mouse_event), offset_(offset) {
+MouseWheelEvent::MouseWheelEvent(const MouseEvent& mouse_event,
+                                 int x_offset,
+                                 int y_offset)
+    : MouseEvent(mouse_event), offset_(x_offset, y_offset) {
   DCHECK(type() == ET_MOUSEWHEEL);
 }
 
diff --git a/ui/base/events/event.h b/ui/base/events/event.h
index 8241ad4..fe746c0 100644
--- a/ui/base/events/event.h
+++ b/ui/base/events/event.h
@@ -406,7 +406,7 @@ class UI_EXPORT MouseWheelEvent : public MouseEvent {
 
   explicit MouseWheelEvent(const base::NativeEvent& native_event);
   explicit MouseWheelEvent(const ScrollEvent& scroll_event);
-  MouseWheelEvent(const MouseEvent& mouse_event, int offset);
+  MouseWheelEvent(const MouseEvent& mouse_event, int x_offset, int y_offset);
 
   template <class T>
   MouseWheelEvent(const MouseWheelEvent& model,
@@ -415,15 +415,16 @@ class UI_EXPORT MouseWheelEvent : public MouseEvent {
                   EventType type,
                   int flags)
       : MouseEvent(model, source, target, type, flags),
-        offset_(model.offset_) {
+        offset_(model.x_offset(), model.y_offset()){
   }
 
   // The amount to scroll. This is in multiples of kWheelDelta.
-  // Note: offset() > 0 means scroll up / left.
-  int offset() const { return offset_; }
+  // Note: x_offset() > 0/y_offset() > 0 means scroll left/up.
+  int x_offset() const { return offset_.x(); }
+  int y_offset() const { return offset_.y(); }
 
  private:
-  int offset_;
+  gfx::Vector2d offset_;
 
   DISALLOW_COPY_AND_ASSIGN(MouseWheelEvent);
 };
diff --git a/ui/base/events/event_utils.h b/ui/base/events/event_utils.h
index 05ce2cd..aaa4a20 100644
--- a/ui/base/events/event_utils.h
+++ b/ui/base/events/event_utils.h
@@ -16,6 +16,7 @@
 
 namespace gfx {
 class Point;
+class Vector2d;
 }
 
 namespace base {
@@ -72,8 +73,9 @@ UI_EXPORT bool IsMouseEvent(const base::NativeEvent& native_event);
 UI_EXPORT int GetChangedMouseButtonFlagsFromNative(
     const base::NativeEvent& native_event);
 
-// Gets the mouse wheel offset from a native event.
-UI_EXPORT int GetMouseWheelOffset(const base::NativeEvent& native_event);
+// Gets the mouse wheel offsets from a native event.
+UI_EXPORT gfx::Vector2d GetMouseWheelOffset(
+    const base::NativeEvent& native_event);
 
 // Gets the touch id from a native event.
 UI_EXPORT int GetTouchId(const base::NativeEvent& native_event);
diff --git a/ui/base/win/events_win.cc b/ui/base/win/events_win.cc
index 5ddc81d..596d8c5 100644
--- a/ui/base/win/events_win.cc
+++ b/ui/base/win/events_win.cc
@@ -246,9 +246,9 @@ int GetChangedMouseButtonFlagsFromNative(
   return 0;
 }
 
-int GetMouseWheelOffset(const base::NativeEvent& native_event) {
+gfx::Vector2d GetMouseWheelOffset(const base::NativeEvent& native_event) {
   DCHECK(native_event.message == WM_MOUSEWHEEL);
-  return GET_WHEEL_DELTA_WPARAM(native_event.wParam);
+  return gfx::Vector2d(0, GET_WHEEL_DELTA_WPARAM(native_event.wParam));
 }
 
 int GetTouchId(const base::NativeEvent& xev) {
diff --git a/ui/base/x/events_x.cc b/ui/base/x/events_x.cc
index e955cbe..d890d65 100644
--- a/ui/base/x/events_x.cc
+++ b/ui/base/x/events_x.cc
@@ -979,23 +979,26 @@ int GetChangedMouseButtonFlagsFromNative(
   return 0;
 }
 
-int GetMouseWheelOffset(const base::NativeEvent& native_event) {
-  float offset = 0;
+gfx::Vector2d GetMouseWheelOffset(const base::NativeEvent& native_event) {
+  float x_offset = 0;
+  float y_offset = 0;
   if (native_event->type == GenericEvent &&
-      GetScrollOffsets(native_event, NULL, &offset, NULL, NULL, NULL))
-    return static_cast<int>(offset);
+      GetScrollOffsets(native_event, &x_offset, &y_offset, NULL, NULL, NULL)) {
+    return gfx::Vector2d(static_cast<int>(x_offset),
+                         static_cast<int>(y_offset));
+  }
 
   int button = native_event->type == GenericEvent ?
       EventButtonFromNative(native_event) : native_event->xbutton.button;
 
   switch (button) {
     case 4:
-      return kWheelScrollAmount;
+      return gfx::Vector2d(0, kWheelScrollAmount);
     case 5:
-      return -kWheelScrollAmount;
+      return gfx::Vector2d(0, -kWheelScrollAmount);
     default:
       // TODO(derat): Do something for horizontal scrolls (buttons 6 and 7)?
-      return 0;
+      return gfx::Vector2d();
   }
 }
 
diff --git a/ui/base/x/events_x_unittest.cc b/ui/base/x/events_x_unittest.cc
index 52a7eb2..5dd5eaa 100644
--- a/ui/base/x/events_x_unittest.cc
+++ b/ui/base/x/events_x_unittest.cc
@@ -42,6 +42,7 @@ void InitButtonEvent(XEvent* event,
 TEST(EventsXTest, ButtonEvents) {
   XEvent event;
   gfx::Point location(5, 10);
+  gfx::Vector2d offset;
 
   InitButtonEvent(&event, true, location, 1, 0);
   EXPECT_EQ(ui::ET_MOUSE_PRESSED, ui::EventTypeFromNative(&event));
@@ -69,7 +70,9 @@ TEST(EventsXTest, ButtonEvents) {
   EXPECT_EQ(0, ui::EventFlagsFromNative(&event));
   EXPECT_EQ(location, ui::EventLocationFromNative(&event));
   EXPECT_TRUE(ui::IsMouseEvent(&event));
-  EXPECT_GT(ui::GetMouseWheelOffset(&event), 0);
+  offset = ui::GetMouseWheelOffset(&event);
+  EXPECT_GT(offset.y(), 0);
+  EXPECT_EQ(0, offset.x());
 
   // Scroll down.
   InitButtonEvent(&event, true, location, 5, 0);
@@ -77,7 +80,9 @@ TEST(EventsXTest, ButtonEvents) {
   EXPECT_EQ(0, ui::EventFlagsFromNative(&event));
   EXPECT_EQ(location, ui::EventLocationFromNative(&event));
   EXPECT_TRUE(ui::IsMouseEvent(&event));
-  EXPECT_LT(ui::GetMouseWheelOffset(&event), 0);
+  offset = ui::GetMouseWheelOffset(&event);
+  EXPECT_LT(offset.y(), 0);
+  EXPECT_EQ(0, offset.x());
 
   // Scroll left, typically.
   InitButtonEvent(&event, true, location, 6, 0);
@@ -85,7 +90,9 @@ TEST(EventsXTest, ButtonEvents) {
   EXPECT_EQ(0, ui::EventFlagsFromNative(&event));
   EXPECT_EQ(location, ui::EventLocationFromNative(&event));
   EXPECT_TRUE(ui::IsMouseEvent(&event));
-  EXPECT_EQ(0, ui::GetMouseWheelOffset(&event));
+  offset = ui::GetMouseWheelOffset(&event);
+  EXPECT_EQ(0, offset.y());
+  EXPECT_EQ(0, offset.x());
 
   // Scroll right, typically.
   InitButtonEvent(&event, true, location, 7, 0);
@@ -93,7 +100,9 @@ TEST(EventsXTest, ButtonEvents) {
   EXPECT_EQ(0, ui::EventFlagsFromNative(&event));
   EXPECT_EQ(location, ui::EventLocationFromNative(&event));
   EXPECT_TRUE(ui::IsMouseEvent(&event));
-  EXPECT_EQ(0, ui::GetMouseWheelOffset(&event));
+  offset = ui::GetMouseWheelOffset(&event);
+  EXPECT_EQ(0, offset.y());
+  EXPECT_EQ(0, offset.x());
 
   // TODO(derat): Test XInput code.
 }
diff --git a/ui/views/controls/menu/submenu_view.cc b/ui/views/controls/menu/submenu_view.cc
index 0e78ffe..0cda4eb 100644
--- a/ui/views/controls/menu/submenu_view.cc
+++ b/ui/views/controls/menu/submenu_view.cc
@@ -236,10 +236,10 @@ bool SubmenuView::OnMouseWheel(const ui::MouseWheelEvent& e) {
   // the next/previous one entirely visible. If enough wasn't scrolled to show
   // any new rows, then just scroll the amount so that smooth scrolling using
   // the trackpad is possible.
-  int delta = abs(e.offset() / ui::MouseWheelEvent::kWheelDelta);
+  int delta = abs(e.y_offset() / ui::MouseWheelEvent::kWheelDelta);
   if (delta == 0)
-    return OnScroll(0, e.offset());
-  for (bool scroll_up = (e.offset() > 0); delta != 0; --delta) {
+    return OnScroll(0, e.y_offset());
+  for (bool scroll_up = (e.y_offset() > 0); delta != 0; --delta) {
     int scroll_target;
     if (scroll_up) {
       if (GetMenuItemAt(first_vis_index)->y() == vis_bounds.y()) {
diff --git a/ui/views/controls/scrollbar/base_scroll_bar.cc b/ui/views/controls/scrollbar/base_scroll_bar.cc
index a62974d..041e9fd 100644
--- a/ui/views/controls/scrollbar/base_scroll_bar.cc
+++ b/ui/views/controls/scrollbar/base_scroll_bar.cc
@@ -192,7 +192,7 @@ bool BaseScrollBar::OnKeyPressed(const ui::KeyEvent& event) {
 }
 
 bool BaseScrollBar::OnMouseWheel(const ui::MouseWheelEvent& event) {
-  ScrollByContentsOffset(event.offset());
+  ScrollByContentsOffset(event.y_offset());
   return true;
 }