Fixes bug where Env/RootWindow would cache the wrong button

ui/base/event.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_EVENT_H_
 #define UI_BASE_EVENT_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/event_types.h"
@@ skipping 169 matching lines @@
 class UI_EXPORT MouseEvent : public LocatedEvent {
  public:
   explicit MouseEvent(const base::NativeEvent& native_event);
 
   // Create a new MouseEvent based on the provided model.
   // Uses the provided |type| and |flags| for the new event.
   // If source / target windows are provided, the model location will be
   // converted from |source| coordinate system to |target| coordinate system.
   template <class T>
   MouseEvent(const MouseEvent& model, T* source, T* target)
-      : LocatedEvent(model, source, target) {
+      : LocatedEvent(model, source, target),
+        changed_button_flags_(model.changed_button_flags_) {
   }
 
   template <class T>
   MouseEvent(const MouseEvent& model,
              T* source,
              T* target,
              EventType type,
              int flags)
-      : LocatedEvent(model, source, target) {
+      : LocatedEvent(model, source, target),
+        changed_button_flags_(model.changed_button_flags_) {
     set_type(type);
     set_flags(flags);
   }
 
   // Used for synthetic events in testing and by the gesture recognizer.
   MouseEvent(EventType type,
              const gfx::Point& location,
              const gfx::Point& root_location,
              int flags);
 
@@ skipping 30 matching lines @@
   static bool IsRepeatedClickEvent(
       const MouseEvent& event1,
       const MouseEvent& event2);
 
   // Get the click count. Can be 1, 2 or 3 for mousedown messages, 0 otherwise.
   int GetClickCount() const;
 
   // Set the click count for a mousedown message. Can be 1, 2 or 3.
   void SetClickCount(int click_count);
 
+  // Identifies the button that changed. During a press this corresponds to the
+  // button that was pressed and during a release this corresponds to the button
+  // that was released.
+  // NOTE: during a press and release flags() contains the complete set of
+  // flags. Use this to determine the button that was pressed or released.
+  int changed_button_flags() const { return changed_button_flags_; }
+
  protected:
   explicit MouseEvent(const MouseEvent& model);
 
  private:
-  gfx::Point root_location_;
-
-  static MouseEvent* last_click_event_;
   // Returns the repeat count based on the previous mouse click, if it is
   // recent enough and within a small enough distance.
   static int GetRepeatCount(const MouseEvent& click_event);
+
+  gfx::Point root_location_;
+
+  // See description above getter for details.
+  int changed_button_flags_;
+
+  static MouseEvent* last_click_event_;
 };
 
 class UI_EXPORT TouchEvent : public LocatedEvent {
  public:
   explicit TouchEvent(const base::NativeEvent& native_event);
 
   // Create a new TouchEvent which is identical to the provided model.
   // If source / target windows are provided, the model location will be
   // converted from |source| coordinate system to |target| coordinate system.
   template <class T>
@@ skipping 205 matching lines @@
   // This value is stored as a bitfield because the number of touch ids varies,
   // but we currently don't need more than 32 touches at a time.
   const unsigned int touch_ids_bitfield_;
 
   DISALLOW_COPY_AND_ASSIGN(GestureEvent);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_EVENT_H_