[Android] Select text when stylus first button is pressed.

ui/events/gesture_detection/motion_event.h

Index: ui/events/gesture_detection/motion_event.h
diff --git a/ui/events/gesture_detection/motion_event.h b/ui/events/gesture_detection/motion_event.h
index 899aeea1c2ae7b8530cfbb1af15e57824bb2b29d..a1ed7ebad6ab47d71e9e567eb3005bcacd75df7f 100644
--- a/ui/events/gesture_detection/motion_event.h
+++ b/ui/events/gesture_detection/motion_event.h
@@ -16,7 +16,7 @@ namespace ui {
 class GESTURE_DETECTION_EXPORT MotionEvent {
  public:
   enum Action {
-    ACTION_DOWN,
+    ACTION_DOWN = 100,
     ACTION_UP,
     ACTION_MOVE,
     ACTION_CANCEL,
@@ -24,6 +24,20 @@ class GESTURE_DETECTION_EXPORT MotionEvent {
     ACTION_POINTER_UP,
   };
 
+  enum ToolType {
+    TOOL_TYPE_UNKNOWN = 200,
+    TOOL_TYPE_FINGER,
+    TOOL_TYPE_STYLUS,
+    TOOL_TYPE_MOUSE,
+  };
+
+  const static int BUTTON_NONE = 0;
+  const static int BUTTON_PRIMARY = 1;
+  const static int BUTTON_SECONDARY = 2;
+  const static int BUTTON_TERTIARY = 4;
+  const static int BUTTON_BACK = 8;
+  const static int BUTTON_FORWARD = 16;
+
   // The implementer promises that |GetPointerId()| will never exceed this.
   enum { MAX_POINTER_ID = 31 };
 
@@ -53,6 +67,8 @@ class GESTURE_DETECTION_EXPORT MotionEvent {
                                size_t historical_index) const = 0;
   virtual float GetHistoricalY(size_t pointer_index,
                                size_t historical_index) const = 0;
+  virtual ToolType GetToolType(size_t pointer_index) const = 0;
+  virtual int GetButtonState() const = 0;
 
   virtual scoped_ptr<MotionEvent> Clone() const = 0;
   virtual scoped_ptr<MotionEvent> Cancel() const = 0;