[MacViews] Implement size constraints for app windows.

chrome/browser/ui/views/apps/native_frame_view_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.
+
+#include "chrome/browser/ui/views/apps/native_frame_view_mac.h"
+
+#import <Cocoa/Cocoa.h>
+
+#import "ui/gfx/mac/coordinate_conversion.h"
+#include "ui/views/widget/widget.h"
+
+// static
+const char NativeFrameViewMac::kViewClassName[] = "NativeFrameViewMac";
+
+NativeFrameViewMac::NativeFrameViewMac(views::Widget* frame)
+    : views::NativeFrameView(frame) {
+}
+
+NativeFrameViewMac::~NativeFrameViewMac() {
+}
+
+gfx::Rect NativeFrameViewMac::GetWindowBoundsForClientBounds(
+    const gfx::Rect& client_bounds) const {
+  NSWindow* ns_window = GetWidget()->GetNativeWindow();
+  gfx::Rect window_bounds = gfx::ScreenRectFromNSRect([ns_window
+      frameRectForContentRect:gfx::ScreenRectToNSRect(client_bounds)]);
+  // Enforce minimum size (1, 1) in case that |client_bounds| is passed with
+  // empty size.
+  if (window_bounds.IsEmpty())
+    window_bounds.set_size(gfx::Size(1, 1));
+  return window_bounds;
+}