Restrict the number of cases where we force the compositor to do a synchronous paint to resizing an…

ui/views/widget/desktop_aura/desktop_window_tree_host_win.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 "ui/views/widget/desktop_aura/desktop_window_tree_host_win.h"
 
 #include "base/win/metro.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/aura/client/aura_constants.h"
@@ skipping 65 matching lines @@
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura)
     : message_handler_(new HWNDMessageHandler(this)),
       native_widget_delegate_(native_widget_delegate),
       desktop_native_widget_aura_(desktop_native_widget_aura),
       content_window_(NULL),
       drag_drop_client_(NULL),
       should_animate_window_close_(false),
       pending_close_(false),
       has_non_client_view_(false),
-      tooltip_(NULL) {
+      tooltip_(NULL),
+      need_synchronous_paint_(false),
+      in_sizing_loop_(false) {
 }
 
 DesktopWindowTreeHostWin::~DesktopWindowTreeHostWin() {
   // WARNING: |content_window_| has been destroyed by the time we get here.
   desktop_native_widget_aura_->OnDesktopWindowTreeHostDestroyed(this);
   DestroyDispatcher();
 }
 
 // static
 aura::Window* DesktopWindowTreeHostWin::GetContentWindowForHWND(HWND hwnd) {
@@ skipping 592 matching lines @@
 
 void DesktopWindowTreeHostWin::HandleCaptureLost() {
   OnHostLostWindowCapture();
 }
 
 void DesktopWindowTreeHostWin::HandleClose() {
   GetWidget()->Close();
 }
 
 bool DesktopWindowTreeHostWin::HandleCommand(int command) {
+  // Windows uses the 4 lower order bits of |notification_code| for type-
+  // specific information so we must exclude this when comparing.
+  static const int sc_mask = 0xFFF0;
+  switch (command & sc_mask) {
+    case SC_RESTORE:
+    case SC_MAXIMIZE:
+      need_synchronous_paint_ = true;
+      break;
+
+    case SC_SIZE:
+      in_sizing_loop_ = true;
+      break;
+
+    default:
+      break;
+  }
   return GetWidget()->widget_delegate()->ExecuteWindowsCommand(command);
 }
 
 void DesktopWindowTreeHostWin::HandleAccelerator(
     const ui::Accelerator& accelerator) {
   GetWidget()->GetFocusManager()->ProcessAccelerator(accelerator);
 }
 
 void DesktopWindowTreeHostWin::HandleCreate() {
   native_widget_delegate_->OnNativeWidgetCreated(true);
@@ skipping 15 matching lines @@
 bool DesktopWindowTreeHostWin::HandleInitialFocus(
     ui::WindowShowState show_state) {
   return GetWidget()->SetInitialFocus(show_state);
 }
 
 void DesktopWindowTreeHostWin::HandleDisplayChange() {
   GetWidget()->widget_delegate()->OnDisplayChanged();
 }
 
 void DesktopWindowTreeHostWin::HandleBeginWMSizeMove() {
+  if (in_sizing_loop_)
+    need_synchronous_paint_ = true;
   native_widget_delegate_->OnNativeWidgetBeginUserBoundsChange();
 }
 
 void DesktopWindowTreeHostWin::HandleEndWMSizeMove() {
+  if (in_sizing_loop_) {
+    need_synchronous_paint_ = false;
+    in_sizing_loop_ = false;
+  }
   native_widget_delegate_->OnNativeWidgetEndUserBoundsChange();
 }
 
 void DesktopWindowTreeHostWin::HandleMove() {
   native_widget_delegate_->OnNativeWidgetMove();
   OnHostMoved(GetBounds().origin());
 }
 
 void DesktopWindowTreeHostWin::HandleWorkAreaChanged() {
   GetWidget()->widget_delegate()->OnWorkAreaChanged();
@@ skipping 136 matching lines @@
                                              LPARAM l_param) {
 }
 
 bool DesktopWindowTreeHostWin::HandleScrollEvent(
     const ui::ScrollEvent& event) {
   SendEventToProcessor(const_cast<ui::ScrollEvent*>(&event));
   return event.handled();
 }
 
 void DesktopWindowTreeHostWin::HandleWindowSizeChanging() {
-  if (compositor())
+  if (compositor() && need_synchronous_paint_) {
     compositor()->FinishAllRendering();
+    // If we received the window size changing notification due to a restore or
+    // maximize operation, then we can reset the need_synchronous_paint_ flag
+    // here. For a sizing operation, the flag will be reset at the end of the
+    // operation.
+    if (!in_sizing_loop_)
+      need_synchronous_paint_ = false;
+  }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopWindowTreeHostWin, private:
 
 Widget* DesktopWindowTreeHostWin::GetWidget() {
   return native_widget_delegate_->AsWidget();
 }
 
 const Widget* DesktopWindowTreeHostWin::GetWidget() const {
@@ skipping 33 matching lines @@
 
 // static
 DesktopWindowTreeHost* DesktopWindowTreeHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura) {
   return new DesktopWindowTreeHostWin(native_widget_delegate,
                                       desktop_native_widget_aura);
 }
 
 }  // namespace views