Support buttons attribute for drag event (chromium side).

content/browser/web_contents/web_drag_dest_mac.mm

 // 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.
 
 #import "content/browser/web_contents/web_drag_dest_mac.h"
 
 #import <Carbon/Carbon.h>
 
 #include "base/strings/sys_string_conversions.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_drag_dest_delegate.h"
 #include "content/public/common/drop_data.h"
 #import "third_party/mozilla/NSPasteboard+Utils.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/base/clipboard/custom_data_helper.h"
 #import "ui/base/dragdrop/cocoa_dnd_util.h"
 #include "ui/base/window_open_disposition.h"
 
 using blink::WebDragOperationsMask;
 using content::DropData;
 using content::OpenURLParams;
 using content::Referrer;
 using content::WebContentsImpl;
 
+namespace {
+
 int GetModifierFlags() {
   int modifier_state = 0;
   UInt32 currentModifiers = GetCurrentKeyModifiers();
   if (currentModifiers & ::shiftKey)
     modifier_state |= blink::WebInputEvent::ShiftKey;
   if (currentModifiers & ::controlKey)
     modifier_state |= blink::WebInputEvent::ControlKey;
   if (currentModifiers & ::optionKey)
     modifier_state |= blink::WebInputEvent::AltKey;
   if (currentModifiers & ::cmdKey)
       modifier_state |= blink::WebInputEvent::MetaKey;
+
+  // The return value of 1 << 0 corresponds to the left mouse button,
+  // 1 << 1 corresponds to the right mouse button,
+  // 1 << n, n >= 2 correspond to other mouse buttons.
+  NSUInteger pressedButtons = [NSEvent pressedMouseButtons];
+
+  if (pressedButtons & (1 << 0))
+      modifier_state |= blink::WebInputEvent::LeftButtonDown;
+  if (pressedButtons & (1 << 1))
+      modifier_state |= blink::WebInputEvent::RightButtonDown;
+  if (pressedButtons & (1 << 2))
+      modifier_state |= blink::WebInputEvent::MiddleButtonDown;
+
   return modifier_state;
 }
 
+}  // namespace
+
 @implementation WebDragDest
 
 // |contents| is the WebContentsImpl representing this tab, used to communicate
 // drag&drop messages to WebCore and handle navigation on a successful drop
 // (if necessary).
 - (id)initWithWebContentsImpl:(WebContentsImpl*)contents {
   if ((self = [super init])) {
     webContents_ = contents;
     canceled_ = false;
   }
@@ skipping 253 matching lines @@
   // Get custom MIME data.
   if ([types containsObject:ui::kWebCustomDataPboardType]) {
     NSData* customData = [pboard dataForType:ui::kWebCustomDataPboardType];
     ui::ReadCustomDataIntoMap([customData bytes],
                               [customData length],
                               &data->custom_data);
   }
 }
 
 @end