Bug 1038488 patch 2 - Remove memset from the operator new of the 4 style structs that have it. r=heycam

This also moves those 4 operator new methods to be inline to match the
style of all of the others.

I audited that all the members of these structs are initialized by all
their constructors (see patch 1).

layout/style/nsStyleStruct.cpp

@@ -156,14 +156,6 @@ nsStyleFont::Init(nsPresContext* aPresContext)
   }
 }
 
-void* 
-nsStyleFont::operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
-  void* result = aContext->AllocateFromShell(sz);
-  if (result)
-    memset(result, 0, sz);
-  return result;
-}
-  
 void 
 nsStyleFont::Destroy(nsPresContext* aContext) {
   this->~nsStyleFont();
@@ -292,14 +284,6 @@ nsStyleMargin::nsStyleMargin(const nsStyleMargin& aSrc)
   MOZ_COUNT_CTOR(nsStyleMargin);
 }
 
-void* 
-nsStyleMargin::operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
-  void* result = aContext->AllocateFromShell(sz);
-  if (result)
-    memset(result, 0, sz);
-  return result;
-}
-  
 void 
 nsStyleMargin::Destroy(nsPresContext* aContext) {
   this->~nsStyleMargin();
@@ -349,14 +333,6 @@ nsStylePadding::nsStylePadding(const nsStylePadding& aSrc)
   MOZ_COUNT_CTOR(nsStylePadding);
 }
 
-void* 
-nsStylePadding::operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
-  void* result = aContext->AllocateFromShell(sz);
-  if (result)
-    memset(result, 0, sz);
-  return result;
-}
-  
 void 
 nsStylePadding::Destroy(nsPresContext* aContext) {
   this->~nsStylePadding();
@@ -480,14 +456,6 @@ nsStyleBorder::~nsStyleBorder()
   }
 }
 
-void*
-nsStyleBorder::operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
-  void* result = aContext->AllocateFromShell(sz);
-  if (result)
-    memset(result, 0, sz);
-  return result;
-}
-
 nsMargin
 nsStyleBorder::GetImageOutset() const
 {

layout/style/nsStyleStruct.h

@@ -88,7 +88,9 @@ public:
   static nscoord ZoomText(nsPresContext* aPresContext, nscoord aSize);
   static nscoord UnZoomText(nsPresContext* aPresContext, nscoord aSize);
 
-  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW;
+  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
+    return aContext->AllocateFromShell(sz);
+  }
   void Destroy(nsPresContext* aContext);
 
   void EnableZoom(nsPresContext* aContext, bool aEnable);
@@ -567,7 +569,9 @@ struct nsStyleMargin {
     MOZ_COUNT_DTOR(nsStyleMargin);
   }
 
-  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW;
+  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
+    return aContext->AllocateFromShell(sz);
+  }
   void Destroy(nsPresContext* aContext);
 
   void RecalcData();
@@ -608,7 +612,9 @@ struct nsStylePadding {
     MOZ_COUNT_DTOR(nsStylePadding);
   }
 
-  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW;
+  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
+    return aContext->AllocateFromShell(sz);
+  }
   void Destroy(nsPresContext* aContext);
 
   void RecalcData();
@@ -795,7 +801,9 @@ struct nsStyleBorder {
   nsStyleBorder(const nsStyleBorder& aBorder);
   ~nsStyleBorder();
 
-  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW;
+  void* operator new(size_t sz, nsPresContext* aContext) CPP_THROW_NEW {
+    return aContext->AllocateFromShell(sz);
+  }
   void Destroy(nsPresContext* aContext);
 
   nsChangeHint CalcDifference(const nsStyleBorder& aOther) const;