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

3 files changed, 15 insertions, 10 deletions

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);