Give nsHTMLReflowState an explicit copy-constructor and assignment operator to fix up mCBReflowState and fix regressions from previous patch. b=143706 r=bzbarsky sr=waterson

layout/base/public/nsHTMLReflowState.h

@@ -262,9 +262,13 @@ struct nsHTMLReflowState {
   static const char* ReasonToString(nsReflowReason aReason);
 #endif
 
-  // Note: The copy constructor is written by the compiler
-  // automatically. You can use that and then override specific values
-  // if you want, or you can call Init as desired...
+  // A simple copy constructor.  (It fixes up |mCBReflowState|, which
+  // can point to |this|, to point to the copy's |this|.)
+  nsHTMLReflowState(const nsHTMLReflowState& aOther);
+
+  // A simple assignment operator.  It does the same fixups as the
+  // copy-consturctor.
+  nsHTMLReflowState& operator=(const nsHTMLReflowState& aOther);
 
   // Initialize a <b>root</b> reflow state with a rendering context to
   // use for measuring things.

layout/generic/nsHTMLReflowState.cpp

@@ -88,6 +88,27 @@ nsHTMLReflowState::ReasonToString(nsReflowReason aReason)
 }
 #endif
 
+nsHTMLReflowState::nsHTMLReflowState(const nsHTMLReflowState& aOther)
+{
+  // Use assignment operator below.
+  *this = aOther;
+}
+
+nsHTMLReflowState&
+nsHTMLReflowState::operator=(const nsHTMLReflowState &aOther)
+{
+  // Copy everything.
+  // XXX This won't work anymore if someone adds member variables that
+  // have nontrivial constructors or assignment operators (e.g.,
+  // nsCOMPtr).
+  memcpy(this, &aOther, sizeof(*this));
+
+  // Fix up the |mCBReflowState| member, which should continue to point
+  // to |this|.
+  if (aOther.mCBReflowState == &aOther)
+    mCBReflowState = this;
+}
+
 // Initialize a <b>root</b> reflow state with a rendering context to
 // use for measuring things.
 nsHTMLReflowState::nsHTMLReflowState(nsIPresContext*      aPresContext,

layout/generic/nsHTMLReflowState.h

@@ -262,9 +262,13 @@ struct nsHTMLReflowState {
   static const char* ReasonToString(nsReflowReason aReason);
 #endif
 
-  // Note: The copy constructor is written by the compiler
-  // automatically. You can use that and then override specific values
-  // if you want, or you can call Init as desired...
+  // A simple copy constructor.  (It fixes up |mCBReflowState|, which
+  // can point to |this|, to point to the copy's |this|.)
+  nsHTMLReflowState(const nsHTMLReflowState& aOther);
+
+  // A simple assignment operator.  It does the same fixups as the
+  // copy-consturctor.
+  nsHTMLReflowState& operator=(const nsHTMLReflowState& aOther);
 
   // Initialize a <b>root</b> reflow state with a rendering context to
   // use for measuring things.

layout/html/base/src/nsHTMLReflowState.cpp

@@ -88,6 +88,27 @@ nsHTMLReflowState::ReasonToString(nsReflowReason aReason)
 }
 #endif
 
+nsHTMLReflowState::nsHTMLReflowState(const nsHTMLReflowState& aOther)
+{
+  // Use assignment operator below.
+  *this = aOther;
+}
+
+nsHTMLReflowState&
+nsHTMLReflowState::operator=(const nsHTMLReflowState &aOther)
+{
+  // Copy everything.
+  // XXX This won't work anymore if someone adds member variables that
+  // have nontrivial constructors or assignment operators (e.g.,
+  // nsCOMPtr).
+  memcpy(this, &aOther, sizeof(*this));
+
+  // Fix up the |mCBReflowState| member, which should continue to point
+  // to |this|.
+  if (aOther.mCBReflowState == &aOther)
+    mCBReflowState = this;
+}
+
 // Initialize a <b>root</b> reflow state with a rendering context to
 // use for measuring things.
 nsHTMLReflowState::nsHTMLReflowState(nsIPresContext*      aPresContext,