Bug 339548. Part 2: Introduce nsRootPresContext.

layout/base/nsDocumentViewer.cpp

@@ -816,6 +816,16 @@ DocumentViewerImpl::InitPresentationStuff(PRBool aDoInitialReflow, PRBool aReena
   return NS_OK;
 }
 
+static nsPresContext*
+CreatePresContext(nsIDocument* aDocument,
+                  nsPresContext::nsPresContextType aType,
+                  nsIView* aContainerView)
+{
+  if (aContainerView)
+    return new nsPresContext(aDocument, aType);
+  return new nsRootPresContext(aDocument, aType);
+}
+
 //-----------------------------------------------
 // This method can be used to initial the "presentation"
 // The aDoCreation indicates whether it should create
@@ -845,10 +855,10 @@ DocumentViewerImpl::InitInternal(nsIWidget* aParentWidget,
       // Create presentation context
       if (mIsPageMode) {
         //Presentation context already created in SetPageMode which is calling this method
+      } else {
+        mPresContext = CreatePresContext(mDocument,
+            nsPresContext::eContext_Galley, containerView);
       }
-      else
-        mPresContext =
-            new nsPresContext(mDocument, nsPresContext::eContext_Galley);
       NS_ENSURE_TRUE(mPresContext, NS_ERROR_OUT_OF_MEMORY);
 
       nsresult rv = mPresContext->Init(mDeviceContext); 
@@ -1912,7 +1922,8 @@ DocumentViewerImpl::Show(void)
 
     // Create presentation context
     NS_ASSERTION(!mPresContext, "Shouldn't have a prescontext if we have no shell!");
-    mPresContext = new nsPresContext(mDocument, nsPresContext::eContext_Galley);
+    mPresContext = CreatePresContext(mDocument,
+        nsPresContext::eContext_Galley, containerView);
     NS_ENSURE_TRUE(mPresContext, NS_ERROR_OUT_OF_MEMORY);
 
     rv = mPresContext->Init(mDeviceContext);
@@ -4245,8 +4256,8 @@ NS_IMETHODIMP DocumentViewerImpl::SetPageMode(PRBool aPageMode, nsIPrintSettings
   NS_ENSURE_STATE(mDocument);
   if (aPageMode)
   {    
-    mPresContext =
-      new nsPresContext(mDocument, nsPresContext::eContext_PageLayout);
+    mPresContext = CreatePresContext(mDocument,
+        nsPresContext::eContext_PageLayout, FindContainerView());
     NS_ENSURE_TRUE(mPresContext, NS_ERROR_OUT_OF_MEMORY);
     mPresContext->SetPaginatedScrolling(PR_TRUE);
     mPresContext->SetPrintSettings(aPrintSettings);

layout/base/nsPresContext.cpp

@@ -1025,7 +1025,7 @@ nsPresContext::Observe(nsISupports* aSubject,
 }
 
 // We may want to replace this with something faster, maybe caching the root prescontext
-nsPresContext*
+nsRootPresContext*
 nsPresContext::RootPresContext()
 {
   nsPresContext* pc = this;
@@ -1040,7 +1040,7 @@ nsPresContext::RootPresContext()
         }
       }
     }
-    return pc;
+    return static_cast<nsRootPresContext*>(pc);
   }
 }
 
@@ -2151,3 +2151,9 @@ nsPresContext::CheckForInterrupt(nsIFrame* aFrame)
   }
   return mHasPendingInterrupt;
 }
+
+nsRootPresContext::nsRootPresContext(nsIDocument* aDocument,
+                                     nsPresContextType aType)
+  : nsPresContext(aDocument, aType)
+{
+}  

layout/base/nsPresContext.h

@@ -151,6 +151,8 @@ enum nsLayoutPhase {
 #define NS_AUTHOR_SPECIFIED_BORDER          (1 << 1)
 #define NS_AUTHOR_SPECIFIED_PADDING         (1 << 2)
 
+class nsRootPresContext;
+
 // An interface for presentation contexts. Presentation contexts are
 // objects that provide an outer context for a presentation shell.
 
@@ -197,7 +199,7 @@ public:
 
   // Find the prescontext for the root of the view manager hierarchy that contains
   // this prescontext.
-  nsPresContext* RootPresContext();
+  nsRootPresContext* RootPresContext();
 
   nsIDocument* Document() const
   {
@@ -1035,7 +1037,7 @@ protected:
 
 protected:
 
-  ~nsPresContext() NS_HIDDEN;
+  virtual ~nsPresContext() NS_HIDDEN;
 
   // these are private, use the list in nsFont.h if you want a public list
   enum {
@@ -1061,6 +1063,11 @@ public:
 
 };
 
+class nsRootPresContext : public nsPresContext {
+public:
+  nsRootPresContext(nsIDocument* aDocument, nsPresContextType aType) NS_HIDDEN;
+};
+
 #ifdef DEBUG
 
 struct nsAutoLayoutPhase {

layout/base/nsPresShell.cpp

@@ -7908,7 +7908,7 @@ PresShell::VerifyIncrementalReflow()
 
   // Create a presentation context to view the new frame tree
   nsCOMPtr<nsPresContext> cx =
-       new nsPresContext(mDocument, mPresContext->IsPaginated() ?
+       new nsRootPresContext(mDocument, mPresContext->IsPaginated() ?
                                         nsPresContext::eContext_PrintPreview :
                                         nsPresContext::eContext_Galley);
   NS_ENSURE_TRUE(cx, PR_FALSE);

layout/printing/nsPrintEngine.cpp

@@ -1915,10 +1915,9 @@ nsPrintEngine::ReflowPrintObject(nsPrintObject * aPO)
   }
 
   // create the PresContext
-  aPO->mPresContext = new nsPresContext(aPO->mDocument,
-                                        mIsCreatingPrintPreview ?
-                                         nsPresContext::eContext_PrintPreview:
-                                         nsPresContext::eContext_Print);
+  aPO->mPresContext = new nsRootPresContext(aPO->mDocument,
+    mIsCreatingPrintPreview ? nsPresContext::eContext_PrintPreview:
+                              nsPresContext::eContext_Print);
   NS_ENSURE_TRUE(aPO->mPresContext, NS_ERROR_OUT_OF_MEMORY);
   aPO->mPresContext->SetPrintSettings(mPrt->mPrintSettings);