Forward Windows touch messages to the renderer

content/browser/renderer_host/render_widget_host_view_win.h

Index: content/browser/renderer_host/render_widget_host_view_win.h
===================================================================
--- content/browser/renderer_host/render_widget_host_view_win.h	(revision 108760)
+++ content/browser/renderer_host/render_widget_host_view_win.h	(working copy)
@@ -141,6 +141,7 @@
     MESSAGE_HANDLER(WM_VSCROLL, OnWheelEvent)
     MESSAGE_HANDLER(WM_CHAR, OnKeyEvent)
     MESSAGE_HANDLER(WM_SYSCHAR, OnKeyEvent)
+    MESSAGE_HANDLER(WM_TOUCH, OnTouchEvent)
     MESSAGE_HANDLER(WM_IME_CHAR, OnKeyEvent)
     MESSAGE_HANDLER(WM_MOUSEACTIVATE, OnMouseActivate)
     MESSAGE_HANDLER(WM_GETOBJECT, OnGetObject)
@@ -247,6 +248,8 @@
       UINT message, WPARAM wparam, LPARAM lparam, BOOL& handled);
   LRESULT OnWheelEvent(
       UINT message, WPARAM wparam, LPARAM lparam, BOOL& handled);
+  LRESULT OnTouchEvent(
+      UINT message, WPARAM wparam, LPARAM lparam, BOOL& handled);
   LRESULT OnMouseActivate(UINT message,
                           WPARAM wparam,
                           LPARAM lparam,
@@ -367,6 +370,43 @@
   // true if the View is not visible.
   bool is_hidden_;
 
+  // Wrapper for maintaining touchstate associated with a WebTouchEvent.
+  class WebTouchState {
+   public:
+    explicit WebTouchState(const CWindowImpl* window);
+
+    // Updates the current touchpoint state with the supplied touches.
+    // Touches will be consumed only if they are of the same type (e.g. down,
+    // up, move). Returns the number of consumed touches.
+    size_t UpdateTouchPoints(TOUCHINPUT* points, size_t count);
+
+    // Marks all active touchpoints as released.
+    bool ReleaseTouchPoints();
+
+    // The contained WebTouchEvent.
+    const WebKit::WebTouchEvent& touch_event() { return touch_event_; }
+
+    // Returns if any touches are modified in the event.
+    bool is_changed() { return touch_event_.changedTouchesLength != 0; }
+
+   private:
+    // Adds a touch point or returns NULL if there's not enough space.
+    WebKit::WebTouchPoint* AddTouchPoint(TOUCHINPUT* touch_input);
+
+    // Copy details from a TOUCHINPUT to an existing WebTouchPoint, returning
+    // true if the resulting point is a stationary move.
+    bool UpdateTouchPoint(WebKit::WebTouchPoint* touch_point,
+                          TOUCHINPUT* touch_input);
+
+    WebKit::WebTouchEvent touch_event_;
+    const CWindowImpl* const window_;
+  };
+
+  // The touch-state. Its touch-points are updated as necessary. A new
+  // touch-point is added from an TOUCHEVENTF_DOWN message, and a touch-point
+  // is removed from the list on an TOUCHEVENTF_UP message.
+  WebTouchState touch_state_;
+
   // True if we're in the midst of a paint operation and should respond to
   // DidPaintRect() notifications by merely invalidating.  See comments on
   // render_widget_host_view.h:DidPaintRect().