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

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

Index: chrome/browser/ui/views/apps/native_app_window_frame_view_mac.mm
diff --git a/chrome/browser/ui/views/apps/native_app_window_frame_view_mac.mm b/chrome/browser/ui/views/apps/native_app_window_frame_view_mac.mm
index 444a6df4035c9770e18b577ca1e5c8d7574335ed..e20efc5c32b1f84517c556874c9c6aba08f45f73 100644
--- a/chrome/browser/ui/views/apps/native_app_window_frame_view_mac.mm
+++ b/chrome/browser/ui/views/apps/native_app_window_frame_view_mac.mm
@@ -6,11 +6,15 @@
 
 #import <Cocoa/Cocoa.h>
 
+#include "extensions/browser/app_window/native_app_window.h"
+#include "ui/base/hit_test.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
 #include "ui/views/widget/widget.h"
 
-NativeAppWindowFrameViewMac::NativeAppWindowFrameViewMac(views::Widget* frame)
-    : views::NativeFrameView(frame) {
+NativeAppWindowFrameViewMac::NativeAppWindowFrameViewMac(
+    views::Widget* frame,
+    extensions::NativeAppWindow* window)
+    : views::NativeFrameView(frame), native_app_window_(window) {
 }
 
 NativeAppWindowFrameViewMac::~NativeAppWindowFrameViewMac() {
@@ -27,3 +31,19 @@ gfx::Rect NativeAppWindowFrameViewMac::GetWindowBoundsForClientBounds(
     window_bounds.set_size(gfx::Size(1, 1));
   return window_bounds;
 }
+
+int NativeAppWindowFrameViewMac::NonClientHitTest(const gfx::Point& point) {
+  if (!bounds().Contains(point))
+    return HTNOWHERE;
+
+  if (GetWidget()->IsFullscreen())
+    return HTCLIENT;
+
+  // Check for possible draggable region in the client area for the frameless
+  // window.
+  SkRegion* draggable_region = native_app_window_->GetDraggableRegion();
+  if (draggable_region && draggable_region->contains(point.x(), point.y()))
+    return HTCAPTION;
+
+  return HTCLIENT;
+}