[Win] Update HWND style when SizeConstraintsChanged.

Previously, caption buttons were set at creation time.
With this CL, minimize and maximize buttons can be added and
removed throughout the lifetime of a window.

BUG=412241

Review URL: https://codereview.chromium.org/581953002

Cr-Commit-Position: refs/heads/master@{#296617}

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

@@ -938,6 +938,7 @@ void DesktopNativeWidgetAura::OnSizeConstraintsChanged() {
                                GetWidget()->widget_delegate()->CanMaximize());
   content_window_->SetProperty(aura::client::kCanResizeKey,
                                GetWidget()->widget_delegate()->CanResize());
+  desktop_window_tree_host_->SizeConstraintsChanged();
 }
 
 void DesktopNativeWidgetAura::RepostNativeEvent(gfx::NativeEvent native_event) {

ui/views/widget/desktop_aura/desktop_window_tree_host.h

@@ -156,6 +156,9 @@ class VIEWS_EXPORT DesktopWindowTreeHost {
 
   // Returns true if the Widget supports translucency.
   virtual bool IsTranslucentWindowOpacitySupported() const = 0;
+
+  // Called when the window's size constraints change.
+  virtual void SizeConstraintsChanged() = 0;
 };
 
 }  // namespace views

ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc

@@ -454,6 +454,10 @@ bool DesktopWindowTreeHostWin::IsTranslucentWindowOpacitySupported() const {
   return ui::win::IsAeroGlassEnabled();
 }
 
+void DesktopWindowTreeHostWin::SizeConstraintsChanged() {
+  message_handler_->SizeConstraintsChanged();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostWin, WindowTreeHost implementation:
 

ui/views/widget/desktop_aura/desktop_window_tree_host_win.h

@@ -104,6 +104,7 @@ class VIEWS_EXPORT DesktopWindowTreeHostWin
   virtual void OnNativeWidgetBlur() OVERRIDE;
   virtual bool IsAnimatingClosed() const OVERRIDE;
   virtual bool IsTranslucentWindowOpacitySupported() const OVERRIDE;
+  virtual void SizeConstraintsChanged() OVERRIDE;
 
   // Overridden from aura::WindowTreeHost:
   virtual ui::EventSource* GetEventSource() OVERRIDE;

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.cc

@@ -850,6 +850,10 @@ bool DesktopWindowTreeHostX11::IsTranslucentWindowOpacitySupported() const {
   return false;
 }
 
+void DesktopWindowTreeHostX11::SizeConstraintsChanged() {
+  UpdateMinAndMaxSize();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostX11, aura::WindowTreeHost implementation:
 

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h

@@ -146,6 +146,7 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
   virtual void OnNativeWidgetBlur() OVERRIDE;
   virtual bool IsAnimatingClosed() const OVERRIDE;
   virtual bool IsTranslucentWindowOpacitySupported() const OVERRIDE;
+  virtual void SizeConstraintsChanged() OVERRIDE;
 
   // Overridden from aura::WindowTreeHost:
   virtual ui::EventSource* GetEventSource() OVERRIDE;

ui/views/widget/widget_hwnd_utils.cc

@@ -81,14 +81,19 @@ void CalculateWindowStylesFromInitParams(
       }
       // Else, no break. Fall through to TYPE_WINDOW.
     case Widget::InitParams::TYPE_WINDOW: {
-      *style |= WS_SYSMENU | WS_CAPTION;
-      bool can_resize = widget_delegate->CanResize();
-      bool can_maximize = widget_delegate->CanMaximize();
-      if (can_maximize) {
-        *style |= WS_OVERLAPPEDWINDOW;
-      } else if (can_resize || params.remove_standard_frame) {
-        *style |= WS_OVERLAPPED | WS_THICKFRAME;
-      }
+      // WS_OVERLAPPEDWINDOW is equivalent to:
+      //   WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU |
+      //   WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX
+      *style |= WS_OVERLAPPEDWINDOW;
+      if (!widget_delegate->CanMaximize())
+        *style &= ~WS_MAXIMIZEBOX;
+      if (!widget_delegate->CanMinimize())
+        *style &= ~WS_MINIMIZEBOX;
+      if (!widget_delegate->CanResize())
+        *style &= ~(WS_THICKFRAME | WS_MAXIMIZEBOX);
+      if (params.remove_standard_frame)
+        *style &= ~(WS_MINIMIZEBOX | WS_MAXIMIZEBOX);
+
       if (native_widget_delegate->IsDialogBox()) {
         *style |= DS_MODALFRAME;
         // NOTE: Turning this off means we lose the close button, which is bad.

ui/views/win/hwnd_message_handler.cc

@@ -868,6 +868,23 @@ void HWNDMessageHandler::SetFullscreen(bool fullscreen) {
     PerformDwmTransition();
 }
 
+void HWNDMessageHandler::SizeConstraintsChanged() {
+  LONG style = GetWindowLong(hwnd(), GWL_STYLE);
+  if (delegate_->CanResize()) {
+    style |= WS_THICKFRAME | WS_MAXIMIZEBOX;
+    if (!delegate_->CanMaximize())
+      style &= ~WS_MAXIMIZEBOX;
+  } else {
+    style &= ~(WS_THICKFRAME | WS_MAXIMIZEBOX);
+  }
+  if (delegate_->CanMinimize()) {
+    style |= WS_MINIMIZEBOX;
+  } else {
+    style &= ~WS_MINIMIZEBOX;
+  }
+  SetWindowLong(hwnd(), GWL_STYLE, style);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // HWNDMessageHandler, InputMethodDelegate implementation:
 

ui/views/win/hwnd_message_handler.h

@@ -205,6 +205,9 @@ class VIEWS_EXPORT HWNDMessageHandler :
 
   void SetFullscreen(bool fullscreen);
 
+  // Updates the window style to reflect whether it can be resized or maximized.
+  void SizeConstraintsChanged();
+
  private:
   typedef std::set<DWORD> TouchIDs;