Bug 1181395 - Avoid runtime conversion or copy of names of window classes on Windows. r=jimm

--HG--
extra : source : 9ba468db37a17a3f39191b8802283e88589e4135

widget/windows/nsUXThemeData.cpp

@@ -173,8 +173,6 @@ nsUXThemeData::UpdateTitlebarInfo(HWND aWnd)
 
   // Query a temporary, visible window with command buttons to get
   // the right metrics. 
-  nsAutoString className;
-  className.AssignLiteral(kClassNameTemp);
   WNDCLASSW wc;
   wc.style         = 0;
   wc.lpfnWndProc   = ::DefWindowProcW;
@@ -185,7 +183,7 @@ nsUXThemeData::UpdateTitlebarInfo(HWND aWnd)
   wc.hCursor       = nullptr;
   wc.hbrBackground = nullptr;
   wc.lpszMenuName  = nullptr;
-  wc.lpszClassName = className.get();
+  wc.lpszClassName = kClassNameTemp;
   ::RegisterClassW(&wc);
 
   // Create a transparent descendant of the window passed in. This
@@ -193,7 +191,7 @@ nsUXThemeData::UpdateTitlebarInfo(HWND aWnd)
   // Note the parent (browser) window is usually still hidden, we
   // don't want to display it, so we can't query it directly.
   HWND hWnd = CreateWindowExW(WS_EX_LAYERED,
-                              className.get(), L"",
+                              kClassNameTemp, L"",
                               WS_OVERLAPPEDWINDOW,
                               0, 0, 0, 0, aWnd, nullptr,
                               nsToolkit::mDllInstance, nullptr);

widget/windows/nsWindow.cpp

@@ -245,9 +245,6 @@ BYTE            nsWindow::sLastMouseButton        = 0;
 // Trim heap on minimize. (initialized, but still true.)
 int             nsWindow::sTrimOnMinimize         = 2;
 
-// Default value for general window class (used when the pref is the empty string).
-const char*     nsWindow::sDefaultMainWindowClass = kClassNameGeneral;
-
 TriStateBool nsWindow::sHasBogusPopupsDropShadowOnMultiMonitor = TRI_UNKNOWN;
 
 DWORD           nsWindow::sFirstEventTime = 0;
@@ -540,7 +537,7 @@ nsWindow::Create(nsIWidget *aParent,
     }
   }
 
-  nsAutoString className;
+  nsString className;
   if (aInitData->mDropShadow) {
     GetWindowPopupClass(className);
   } else {
@@ -2929,7 +2926,7 @@ nsWindow::MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen)
 // Return some native data according to aDataType
 void* nsWindow::GetNativeData(uint32_t aDataType)
 {
-  nsAutoString className;
+  nsString className;
   switch (aDataType) {
     case NS_NATIVE_TMP_WINDOW:
       GetWindowClass(className);
@@ -7562,7 +7559,7 @@ void nsWindow::GetMainWindowClass(nsAString& aClass)
   NS_PRECONDITION(aClass.IsEmpty(), "aClass should be empty string");
   nsresult rv = Preferences::GetString("ui.window_class_override", &aClass);
   if (NS_FAILED(rv) || aClass.IsEmpty()) {
-    aClass.AssignASCII(sDefaultMainWindowClass);
+    aClass.AssignLiteral(kClassNameGeneral);
   }
 }
 

widget/windows/nsWindow.h

@@ -499,7 +499,6 @@ protected:
   static bool           sJustGotActivate;
   static bool           sIsInMouseCapture;
   static int            sTrimOnMinimize;
-  static const char*    sDefaultMainWindowClass;
 
   // Always use the helper method to read this property.  See bug 603793.
   static TriStateBool   sHasBogusPopupsDropShadowOnMultiMonitor;

widget/windows/nsWindowDefs.h

@@ -213,11 +213,11 @@ typedef enum
  * touchpad scrolling or screen readers.
  */
 const uint32_t kMaxClassNameLength   = 40;
-const char kClassNameHidden[]        = "MozillaHiddenWindowClass";
-const char kClassNameGeneral[]       = "MozillaWindowClass";
-const char kClassNameDialog[]        = "MozillaDialogClass";
-const char kClassNameDropShadow[]    = "MozillaDropShadowWindowClass";
-const char kClassNameTemp[]          = "MozillaTempWindowClass";
+const wchar_t kClassNameHidden[]     = L"MozillaHiddenWindowClass";
+const wchar_t kClassNameGeneral[]    = L"MozillaWindowClass";
+const wchar_t kClassNameDialog[]     = L"MozillaDialogClass";
+const wchar_t kClassNameDropShadow[] = L"MozillaDropShadowWindowClass";
+const wchar_t kClassNameTemp[]       = L"MozillaTempWindowClass";
 
 /**************************************************************
  *