Bug 586909: Discard D2D surfaces for a window when it's hidden. r=robarnold

widget/src/windows/nsWindow.cpp

@@ -176,6 +176,7 @@
 #endif
 #include "LayerManagerOGL.h"
 #endif
+#include "BasicLayers.h"
 
 #if !defined(WINCE)
 #include "nsUXThemeConstants.h"
@@ -1141,6 +1142,12 @@ NS_METHOD nsWindow::Show(PRBool bState)
   // SetWindowPos would get the correct answer.
   mIsVisible = bState;
 
+#ifdef CAIRO_HAS_D2D_SURFACE
+  if (!mIsVisible && wasVisible) {
+      ClearD2DSurface();
+  }
+#endif
+
   if (mWnd) {
     if (bState) {
       if (!wasVisible && mWindowType == eWindowType_toplevel) {
@@ -7861,6 +7868,31 @@ VOID CALLBACK nsWindow::HookTimerForPopups(HWND hwnd, UINT uMsg, UINT idEvent, D
 }
 #endif // WinCE
 
+#ifdef CAIRO_HAS_D2D_SURFACE
+BOOL CALLBACK nsWindow::ClearD2DSurfaceCallback(HWND aWnd, LPARAM aMsg)
+{
+    nsWindow *window = nsWindow::GetNSWindowPtr(aWnd);
+    if (window) {
+        window->ClearD2DSurface();
+    }  
+    return TRUE;
+}
+
+void
+nsWindow::ClearD2DSurface()
+{
+    mD2DWindowSurface = nsnull;
+    if (gfxWindowsPlatform::GetPlatform()->GetRenderMode() ==
+        gfxWindowsPlatform::RENDER_DIRECT2D) {
+        // The layer manager holds onto a bunch of buffers created with create
+        // similar surface. This can consume quite a bit of VMEM for each tab,
+        // if a window is hidden we clear the layer manager to conserve VRAM.
+        mLayerManager = nsnull;
+    }
+    ::EnumChildWindows(mWnd, nsWindow::ClearD2DSurfaceCallback, NULL);
+}
+#endif
+
 static PRBool IsDifferentThreadWindow(HWND aWnd)
 {
   return ::GetCurrentThreadId() != ::GetWindowThreadProcessId(aWnd, NULL);

widget/src/windows/nsWindow.h

@@ -288,6 +288,9 @@ protected:
   static LRESULT CALLBACK MozSpecialWndProc(int code, WPARAM wParam, LPARAM lParam);
   static LRESULT CALLBACK MozSpecialMouseProc(int code, WPARAM wParam, LPARAM lParam);
   static VOID    CALLBACK HookTimerForPopups( HWND hwnd, UINT uMsg, UINT idEvent, DWORD dwTime );
+#ifdef CAIRO_HAS_D2D_SURFACE
+  static BOOL    CALLBACK ClearD2DSurfaceCallback(HWND aChild, LPARAM aParam);
+#endif
 
   /**
    * Window utilities
@@ -445,6 +448,9 @@ protected:
 #ifdef ACCESSIBILITY
   static STDMETHODIMP_(LRESULT) LresultFromObject(REFIID riid, WPARAM wParam, LPUNKNOWN pAcc);
 #endif // ACCESSIBILITY
+#ifdef CAIRO_HAS_D2D_SURFACE
+  void                    ClearD2DSurface();
+#endif
 
 protected:
   nsCOMPtr<nsIWidget>   mParent;