Exclude caption button bounds from non-client frame hit testing

chrome/browser/ui/views/frame/glass_browser_frame_view.cc

 // 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.
 
 #include "chrome/browser/ui/views/frame/glass_browser_frame_view.h"
 
+#include <dwmapi.h>
 #include <utility>
 
 #include "base/strings/utf_string_conversions.h"
 #include "base/win/windows_version.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/app/chrome_dll_resource.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/themes/theme_properties.h"
 #include "chrome/browser/ui/layout_constants.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/profiles/profile_indicator_icon.h"
 #include "chrome/browser/ui/views/tabs/tab.h"
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 #include "chrome/browser/ui/views/toolbar/toolbar_view.h"
 #include "components/prefs/pref_service.h"
 #include "components/signin/core/browser/signin_header_helper.h"
 #include "components/signin/core/common/profile_management_switches.h"
 #include "grit/theme_resources.h"
 #include "skia/ext/image_operations.h"
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/resource/resource_bundle_win.h"
 #include "ui/base/theme_provider.h"
 #include "ui/display/win/dpi.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/geometry/dip_util.h"
 #include "ui/gfx/icon_util.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/scoped_canvas.h"
 #include "ui/resources/grit/ui_resources.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/layout/layout_constants.h"
 #include "ui/views/resources/grit/views_resources.h"
 #include "ui/views/win/hwnd_util.h"
 #include "ui/views/window/client_view.h"
 
@@ skipping 22 matching lines @@
 const int kNewTabCaptionRestoredSpacing = 5;
 // In maximized mode, where the New Tab button and the caption buttons are at
 // similar vertical coordinates, we need to reserve a larger, 16 px gap to avoid
 // looking too cluttered.
 const int kNewTabCaptionMaximizedSpacing = 16;
 // Height of the profile switcher button. Same as the height of the Windows 7/8
 // caption buttons.
 // TODO(bsep): Windows 10 caption buttons look very different and we would like
 // the profile switcher button to match on that platform.
 const int kProfileSwitcherButtonHeight = 20;
+// There is a small one-pixel strip right above the caption buttons in which the
+// resize border "peeks" through.
+const int kCaptionButtonTopInset = 1;
 
 // Converts the |image| to a Windows icon and returns the corresponding HICON
 // handle. |image| is resized to desired |width| and |height| if needed.
 base::win::ScopedHICON CreateHICONFromSkBitmapSizedTo(
     const gfx::ImageSkia& image,
     int width,
     int height) {
   return IconUtil::CreateHICONFromSkBitmap(
       width == image.width() && height == image.height()
           ? *image.bitmap()
@@ skipping 155 matching lines @@
   gfx::Rect sys_menu_region(client_border_thickness,
                             display::win::GetSystemMetricsInDIP(SM_CYSIZEFRAME),
                             display::win::GetSystemMetricsInDIP(SM_CXSMICON),
                             display::win::GetSystemMetricsInDIP(SM_CYSMICON));
   if (sys_menu_region.Contains(point))
     return (frame_component == HTCLIENT) ? HTCLIENT : HTSYSMENU;
 
   if (frame_component != HTNOWHERE)
     return frame_component;
 
+  // On Windows 8+, the caption buttons are almost butted up to the top right
+  // corner of the window. This code ensures the mouse isn't set to a size
+  // cursor while hovering over the caption buttons, thus giving the incorrect
+  // impression that the user can resize the window.
+  if (base::win::GetVersion() >= base::win::VERSION_WIN8) {
+    RECT button_bounds = {0};
+    if (SUCCEEDED(DwmGetWindowAttribute(views::HWNDForWidget(frame()),
+                                        DWMWA_CAPTION_BUTTON_BOUNDS,
+                                        &button_bounds,
+                                        sizeof(button_bounds)))) {
+      gfx::Rect buttons = gfx::ConvertRectToDIP(display::win::GetDPIScale(),
+                                                gfx::Rect(button_bounds));
+      // The sizing region at the window edge above the caption buttons is
+      // 1 px regardless of scale factor. If we inset by 1 before converting
+      // to DIPs, the precision loss might eliminate this region entirely. The
+      // best we can do is to inset after conversion. This guarantees we'll
+      // show the resize cursor when resizing is possible. The cost of which
+      // is also maybe showing it over the portion of the DIP that isn't the
+      // outermost pixel.
+      buttons.Inset(0, kCaptionButtonTopInset, 0, 0);
+      if (buttons.Contains(point))
+        return HTNOWHERE;
+    }
+  }
+
   int top_border_thickness = FrameTopBorderThickness(false);
   // We want the resize corner behavior to apply to the kResizeCornerWidth
   // pixels at each end of the top and bottom edges.  Because |point|'s x
   // coordinate is based on the DWM-inset portion of the window (so, it's 0 at
   // the first pixel inside the left DWM margin), we need to subtract the DWM
   // margin thickness, which we calculate as the total frame border thickness
   // minus the nonclient border thickness.
   const int dwm_margin = FrameBorderThickness() - client_border_thickness;
   int window_component = GetHTComponentForFrame(
       point, top_border_thickness, client_border_thickness,
@@ skipping 419 matching lines @@
   static bool initialized = false;
   if (!initialized) {
     for (int i = 0; i < kThrobberIconCount; ++i) {
       throbber_icons_[i] =
           ui::LoadThemeIconFromResourcesDataDLL(IDI_THROBBER_01 + i);
       DCHECK(throbber_icons_[i]);
     }
     initialized = true;
   }
 }