Bug 1596339 Part 3 - Implement operator<< for LogicalSize, and use it in frame tree dump. r=dholbert

Note: The output format of BaseSize is "3 x 5", so a pair of parentheses
is added around %s in "logical-size=(%s)" to make it looks better.

Differential Revision: https://phabricator.services.mozilla.com/D52964

--HG--
extra : moz-landing-system : lando

layout/generic/WritingModes.h

@@ -1041,6 +1041,11 @@ class LogicalSize {
     return *this;
   }
 
+  friend std::ostream& operator<<(std::ostream& aStream,
+                                  const LogicalSize& aSize) {
+    return aStream << aSize.mSize;
+  }
+
  private:
   friend class LogicalRect;
 

layout/generic/nsFrame.cpp

@@ -7847,8 +7847,8 @@ void nsIFrame::ListGeneric(nsACString& aTo, const char* aPrefix,
 
   mozilla::WritingMode wm = GetWritingMode();
   if (wm.IsVertical() || wm.IsBidiRTL()) {
-    aTo += nsPrintfCString(" wm=%s logical-size={%d,%d}", ToString(wm).c_str(),
-                           ISize(), BSize());
+    aTo += nsPrintfCString(" wm=%s logical-size=(%s)", ToString(wm).c_str(),
+                           ToString(GetLogicalSize()).c_str());
   }
 
   nsIFrame* parent = GetParent();