[MacViews] Enable dragging a window by its caption/draggable areas.

chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.mm

 // Copyright 2015 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 "chrome/browser/ui/views/apps/chrome_native_app_window_views_mac.h"
 
+#import <Cocoa/Cocoa.h>
+
+#import "base/mac/scoped_nsobject.h"
 #include "chrome/browser/apps/app_shim/extension_app_shim_handler_mac.h"
-#include "chrome/browser/ui/views/apps/app_window_native_widget_mac.h"
-#include "chrome/browser/ui/views/apps/native_app_window_frame_view_mac.h"
+#import "chrome/browser/ui/views/apps/app_window_native_widget_mac.h"
+#import "chrome/browser/ui/views/apps/native_app_window_frame_view_mac.h"
+
+@interface NSView (WebContentsView)
+- (void)setMouseDownCanMoveWindow:(BOOL)can_move;
+@end
 
 ChromeNativeAppWindowViewsMac::ChromeNativeAppWindowViewsMac()
     : is_hidden_with_app_(false) {
 }
 
 ChromeNativeAppWindowViewsMac::~ChromeNativeAppWindowViewsMac() {
 }
 
 void ChromeNativeAppWindowViewsMac::OnBeforeWidgetInit(
     const extensions::AppWindow::CreateParams& create_params,
     views::Widget::InitParams* init_params,
     views::Widget* widget) {
   DCHECK(!init_params->native_widget);
   init_params->remove_standard_frame = IsFrameless();
   init_params->native_widget = new AppWindowNativeWidgetMac(widget, this);
   ChromeNativeAppWindowViews::OnBeforeWidgetInit(create_params, init_params,
                                                  widget);
 }
 
 views::NonClientFrameView*
 ChromeNativeAppWindowViewsMac::CreateStandardDesktopAppFrame() {
-  return new NativeAppWindowFrameViewMac(widget());
+  return new NativeAppWindowFrameViewMac(widget(), this);
 }
 
 views::NonClientFrameView*
 ChromeNativeAppWindowViewsMac::CreateNonStandardAppFrame() {
-  return new NativeAppWindowFrameViewMac(widget());
+  return new NativeAppWindowFrameViewMac(widget(), this);
 }
 
 void ChromeNativeAppWindowViewsMac::Show() {
   if (is_hidden_with_app_) {
     // If there is a shim to gently request attention, return here. Otherwise
     // show the window as usual.
     if (apps::ExtensionAppShimHandler::ActivateAndRequestUserAttentionForWindow(
             app_window())) {
       return;
     }
   }
 
   ChromeNativeAppWindowViews::Show();
 }
 
 void ChromeNativeAppWindowViewsMac::ShowInactive() {
   if (is_hidden_with_app_)
     return;
 
   ChromeNativeAppWindowViews::ShowInactive();
 }
 
 void ChromeNativeAppWindowViewsMac::FlashFrame(bool flash) {
   apps::ExtensionAppShimHandler::RequestUserAttentionForWindow(
       app_window(), flash ? apps::APP_SHIM_ATTENTION_CRITICAL
                           : apps::APP_SHIM_ATTENTION_CANCEL);
 }
 
+void ChromeNativeAppWindowViewsMac::UpdateDraggableRegions(
+    const std::vector<extensions::DraggableRegion>& regions) {
+  ChromeNativeAppWindowViews::UpdateDraggableRegions(regions);
+
+  NSView* web_contents_view = app_window()->web_contents()->GetNativeView();
+  [web_contents_view setMouseDownCanMoveWindow:YES];
+}
+
 void ChromeNativeAppWindowViewsMac::ShowWithApp() {
   is_hidden_with_app_ = false;
   if (!app_window()->is_hidden())
     ShowInactive();
 }
 
 void ChromeNativeAppWindowViewsMac::HideWithApp() {
   is_hidden_with_app_ = true;
   ChromeNativeAppWindowViews::Hide();
 }