Bug 403565. Give each contentviewer it's own device context. r+sr=bzbarsky

docshell/base/nsDocShell.cpp

@@ -3782,15 +3782,6 @@ nsDocShell::SetParentWidget(nsIWidget * aParentWidget)
 {
     mParentWidget = aParentWidget;
 
-    if (!mParentWidget) {
-        // If the parent widget is set to null we don't want to hold
-        // on to the current device context any more since it is
-        // associated with the parent widget we no longer own. We'll
-        // need to create a new device context if one is needed again.
-
-        mDeviceContext = nsnull;
-    }
-
     return NS_OK;
 }
 
@@ -5112,24 +5103,6 @@ nsDocShell::EnsureContentViewer()
     return rv;
 }
 
-NS_IMETHODIMP
-nsDocShell::EnsureDeviceContext()
-{
-    if (mDeviceContext)
-        return NS_OK;
-
-    mDeviceContext = do_CreateInstance(kDeviceContextCID);
-    NS_ENSURE_TRUE(mDeviceContext, NS_ERROR_FAILURE);
-
-    nsCOMPtr<nsIWidget> widget;
-    GetMainWidget(getter_AddRefs(widget));
-    NS_ENSURE_TRUE(widget, NS_ERROR_FAILURE);
-
-    mDeviceContext->Init(widget->GetNativeData(NS_NATIVE_WIDGET));
-
-    return NS_OK;
-}
-
 nsresult
 nsDocShell::CreateAboutBlankContentViewer(nsIPrincipal* aPrincipal)
 {
@@ -6272,13 +6245,16 @@ nsDocShell::SetupNewViewer(nsIContentViewer * aNewViewer)
     nsCOMPtr<nsIWidget> widget;
     NS_ENSURE_SUCCESS(GetMainWidget(getter_AddRefs(widget)), NS_ERROR_FAILURE);
 
+    nsCOMPtr<nsIDeviceContext> deviceContext;
     if (widget) {
-        NS_ENSURE_SUCCESS(EnsureDeviceContext(), NS_ERROR_FAILURE);
+        deviceContext = do_CreateInstance(kDeviceContextCID);
+        NS_ENSURE_TRUE(deviceContext, NS_ERROR_FAILURE);
+        deviceContext->Init(widget->GetNativeData(NS_NATIVE_WIDGET));
     }
 
     nsRect bounds(x, y, cx, cy);
 
-    if (NS_FAILED(mContentViewer->Init(widget, mDeviceContext, bounds))) {
+    if (NS_FAILED(mContentViewer->Init(widget, deviceContext, bounds))) {
         mContentViewer = nsnull;
         NS_ERROR("ContentViewer Initialization failed");
         return NS_ERROR_FAILURE;

docshell/base/nsDocShell.h

@@ -240,7 +240,6 @@ protected:
 
     // Content Viewer Management
     NS_IMETHOD EnsureContentViewer();
-    NS_IMETHOD EnsureDeviceContext();
     // aPrincipal can be passed in if the caller wants.  If null is
     // passed in, the about:blank principal will end up being used.
     nsresult CreateAboutBlankContentViewer(nsIPrincipal* aPrincipal);
@@ -600,7 +599,6 @@ protected:
     nsRect                     mBounds; // Dimensions of the docshell
     nsCOMPtr<nsIContentViewer> mContentViewer;
     nsCOMPtr<nsIDocumentCharsetInfo> mDocumentCharsetInfo;
-    nsCOMPtr<nsIDeviceContext> mDeviceContext;
     nsCOMPtr<nsIWidget>        mParentWidget;
     nsCOMPtr<nsIPrefBranch>    mPrefs;
 

docshell/base/nsWebShell.cpp

@@ -565,7 +565,6 @@ nsWebShell::~nsWebShell()
              // recursively if the refcount is allowed to remain 0
 
   mContentViewer=nsnull;
-  mDeviceContext=nsnull;
 
   InitFrameData();
 

layout/base/nsDocumentViewer.cpp

@@ -1505,10 +1505,7 @@ DocumentViewerImpl::Destroy()
     mPreviousViewer = nsnull;
   }
 
-  if (mDeviceContext) {
-    mDeviceContext->FlushFontCache();
-    mDeviceContext = nsnull;
-  }
+  mDeviceContext = nsnull;
 
   if (mPresShell) {
     // Break circular reference (or something)
@@ -1959,10 +1956,6 @@ DocumentViewerImpl::Hide(void)
     return NS_OK;
   }
 
-  if (mDeviceContext) {
-    mDeviceContext->FlushFontCache();
-  }
-
   // Break circular reference (or something)
   mPresShell->EndObservingDocument();
   nsCOMPtr<nsISelection> selection;