Add member variables to pres context to track, during reflow and intrinsic sizing, the current inflation container and its width. (Bug 706609, patch 2) r=roc

This is the first of three patches to rework the way we handle getting
the font inflation container and width data during reflow, which are
needed so that we can sometimes honor inflation during intrinsic width
calculation (which we need to do to make some form controls inflate
correctly).

layout/base/nsPresContext.h

@@ -1047,6 +1047,22 @@ protected:
   // charset rather than explicitly specified as a lang attribute).
   nsIAtom*              mLanguage;      // [STRONG]
 
+public:
+  // The following are public member variables so that we can use them
+  // with mozilla::AutoToggle or mozilla::AutoRestore.
+
+  // The frame that is the container for font size inflation for the
+  // reflow or intrinsic width computation currently happening.  If this
+  // frame is null, then font inflation should not be performed.
+  nsIFrame*             mCurrentInflationContainer; // [WEAK]
+
+  // The content-rect width of mCurrentInflationContainer.  If
+  // mCurrentInflationContainer is currently in reflow, this is its new
+  // width, which is not yet set on its rect.
+  nscoord               mCurrentInflationContainerWidth;
+
+protected:
+
   nsRefPtrHashtable<nsVoidPtrHashKey, nsImageLoader>
                         mImageLoaders[IMAGE_LOAD_TYPE_COUNT];