Bug 678222 - Fix build with clang and c++0x; r=roc

Change AppUnitsPerDevPixel to return a PRUint32. It should never return
negative values and it is used in initializer lists that expect unsigned
values, which is not valid c++0x.
I have also change the member variables to be unsigned and converted
a sentinel value to use 0 instead of -1. UINT32_MAX should work fine too
if you like it better.

gfx/src/nsDeviceContext.h

@@ -115,7 +115,7 @@ public:
      * is usually a factor of AppUnitsPerCSSPixel(), although that is
      * not guaranteed.
      */
-    PRInt32 AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
+    PRUint32 AppUnitsPerDevPixel() const { return mAppUnitsPerDevPixel; }
 
     /**
      * Convert device pixels which is used for gfx/thebes to nearest
@@ -311,7 +311,7 @@ protected:
     nscoord  mWidth;
     nscoord  mHeight;
     PRUint32 mDepth;
-    PRInt32  mAppUnitsPerDevPixel;
+    PRUint32  mAppUnitsPerDevPixel;
     PRInt32  mAppUnitsPerDevNotScaledPixel;
     PRInt32  mAppUnitsPerPhysicalInch;
     float    mPixelScale;

gfx/src/nsFontMetrics.cpp

@@ -98,7 +98,7 @@ public:
 } // anon namespace
 
 nsFontMetrics::nsFontMetrics()
-    : mDeviceContext(nsnull), mP2A(-1), mTextRunRTL(PR_FALSE)
+    : mDeviceContext(nsnull), mP2A(0), mTextRunRTL(PR_FALSE)
 {
 }
 
@@ -113,7 +113,7 @@ nsFontMetrics::Init(const nsFont& aFont, nsIAtom* aLanguage,
                     nsDeviceContext *aContext,
                     gfxUserFontSet *aUserFontSet)
 {
-    NS_ABORT_IF_FALSE(mP2A == -1, "already initialized");
+    NS_ABORT_IF_FALSE(mP2A == 0, "already initialized");
 
     mFont = aFont;
     mLanguage = aLanguage;

gfx/src/nsFontMetrics.h

@@ -227,7 +227,7 @@ public:
     gfxFontGroup* GetThebesFontGroup() { return mFontGroup; }
     gfxUserFontSet* GetUserFontSet() { return mFontGroup->GetUserFontSet(); }
 
-    PRInt32 AppUnitsPerDevPixel() { return mP2A; }
+    PRUint32 AppUnitsPerDevPixel() { return mP2A; }
 
 protected:
     const gfxFont::Metrics& GetMetrics() const;
@@ -236,7 +236,7 @@ protected:
     nsRefPtr<gfxFontGroup> mFontGroup;
     nsCOMPtr<nsIAtom> mLanguage;
     nsDeviceContext *mDeviceContext;
-    PRInt32 mP2A;
+    PRUint32 mP2A;
     PRPackedBool mTextRunRTL;
 };
 

gfx/src/nsRenderingContext.h

@@ -70,7 +70,7 @@ public:
     // These accessors will never return null.
     gfxContext *ThebesContext() { return mThebes; }
     nsDeviceContext *DeviceContext() { return mDeviceContext; }
-    PRInt32 AppUnitsPerDevPixel() { return mP2A; }
+    PRUint32 AppUnitsPerDevPixel() { return mP2A; }
 
     // Graphics state
 

layout/base/nsPresContext.h

@@ -592,7 +592,7 @@ public:
   }
   
   static PRInt32 AppUnitsPerCSSPixel() { return nsDeviceContext::AppUnitsPerCSSPixel(); }
-  PRInt32 AppUnitsPerDevPixel() const  { return mDeviceContext->AppUnitsPerDevPixel(); }
+  PRUint32 AppUnitsPerDevPixel() const  { return mDeviceContext->AppUnitsPerDevPixel(); }
   static PRInt32 AppUnitsPerCSSInch() { return nsDeviceContext::AppUnitsPerCSSInch(); }
 
   static nscoord CSSPixelsToAppUnits(PRInt32 aPixels)

view/src/nsViewManager.h

@@ -253,7 +253,7 @@ public: // NOT in nsIViewManager, so private to the view module
   // pending updates.
   void PostPendingUpdate() { RootViewManager()->mHasPendingUpdates = PR_TRUE; }
 
-  PRInt32 AppUnitsPerDevPixel() const
+  PRUint32 AppUnitsPerDevPixel() const
   {
     return mContext->AppUnitsPerDevPixel();
   }

xpfe/appshell/src/nsXULWindow.cpp

@@ -2083,7 +2083,7 @@ NS_IMETHODIMP nsXULWindow::SetXULBrowserWindow(nsIXULBrowserWindow * aXULBrowser
 // nsXULWindow: Accessors
 //*****************************************************************************
 
-PRInt32 nsXULWindow::AppUnitsPerDevPixel()
+PRUint32 nsXULWindow::AppUnitsPerDevPixel()
 {
   if (mWindow && mWindow->GetDeviceContext()) {
     mAppPerDev = mWindow->GetDeviceContext()->AppUnitsPerDevPixel();

xpfe/appshell/src/nsXULWindow.h

@@ -147,7 +147,7 @@ protected:
    void       SetContentScrollbarVisibility(PRBool aVisible);
    PRBool     GetContentScrollbarVisibility();
    void       PersistentAttributesDirty(PRUint32 aDirtyFlags);
-   PRInt32    AppUnitsPerDevPixel();
+   PRUint32   AppUnitsPerDevPixel();
 
    nsChromeTreeOwner*      mChromeTreeOwner;
    nsContentTreeOwner*     mContentTreeOwner;