Bug 1575305 Part 4 - Improve column set log. r=dbaron

1. Add `this` to the log so that it's easier to debug a nested column
balancing

2. Print the struct fields the same as their names.

Differential Revision: https://phabricator.services.mozilla.com/D42711

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

layout/generic/nsColumnSetFrame.cpp

@@ -419,12 +419,6 @@ nsColumnSetFrame::ReflowConfig nsColumnSetFrame::ChooseColumnStrategy(
     colBSize = std::max(colBSize, nsPresContext::CSSPixelsToAppUnits(1));
   }
 
-  COLUMN_SET_LOG(
-      "%s: numColumns=%d, colISize=%d, expectedISizeLeftOver=%d,"
-      " colBSize=%d, colGap=%d, isBalancing %d",
-      __func__, numColumns, colISize, expectedISizeLeftOver, colBSize, colGap,
-      isBalancing);
-
   ReflowConfig config;
   config.mBalanceColCount = numColumns;
   config.mColISize = colISize;
@@ -437,6 +431,13 @@ nsColumnSetFrame::ReflowConfig nsColumnSetFrame::ChooseColumnStrategy(
   config.mComputedBSize = computedBSize;
   config.mConsumedBSize = consumedBSize;
 
+  COLUMN_SET_LOG(
+      "%s: this=%p, mBalanceColCount=%d, mColISize=%d, "
+      "mExpectedISizeLeftOver=%d, mColGap=%d, mColMaxBSize=%d, mIsBalancing=%d",
+      __func__, this, config.mBalanceColCount, config.mColISize,
+      config.mExpectedISizeLeftOver, config.mColGap, config.mColMaxBSize,
+      config.mIsBalancing);
+
   return config;
 }
 
@@ -722,6 +723,11 @@ nsColumnSetFrame::ColumnBalanceData nsColumnSetFrame::ReflowChildren(
       LogicalSize availSize(wm, aConfig.mColISize, aConfig.mColMaxBSize);
       if (aUnboundedLastColumn && columnCount == aConfig.mBalanceColCount - 1) {
         availSize.BSize(wm) = GetAvailableContentBSize(aReflowInput);
+
+        COLUMN_SET_LOG(
+            "%s: Measuring content block-size, change available block-size "
+            "from %d to %d",
+            __func__, aConfig.mColMaxBSize, availSize.BSize(wm));
       }
 
       if (reflowNext) {
@@ -998,8 +1004,11 @@ nsColumnSetFrame::ColumnBalanceData nsColumnSetFrame::ReflowChildren(
 
   colData.mFeasible =
       allFit && aStatus.IsFullyComplete() && !aStatus.IsTruncated();
-  COLUMN_SET_LOG("%s: Done column reflow pass: %s", __func__,
-                 colData.mFeasible ? "Feasible :)" : "Infeasible :(");
+  COLUMN_SET_LOG(
+      "%s: Done column reflow pass: %s, mMaxBSize=%d, mSumBSize=%d, "
+      "mMaxOverflowingBSize=%d",
+      __func__, colData.mFeasible ? "Feasible :)" : "Infeasible :(",
+      colData.mMaxBSize, colData.mSumBSize, colData.mMaxOverflowingBSize);
 
   return colData;
 }
@@ -1082,9 +1091,10 @@ void nsColumnSetFrame::FindBestBalanceBSize(const ReflowInput& aReflowInput,
       }
     }
 
-    COLUMN_SET_LOG("%s: KnownInfeasibleBSize=%d, KnownFeasibleBSize=%d",
-                   __func__, aConfig.mKnownInfeasibleBSize,
-                   aConfig.mKnownFeasibleBSize);
+    COLUMN_SET_LOG(
+        "%s: this=%p, mKnownInfeasibleBSize=%d, mKnownFeasibleBSize=%d",
+        __func__, this, aConfig.mKnownInfeasibleBSize,
+        aConfig.mKnownFeasibleBSize);
 
     if (aConfig.mKnownInfeasibleBSize >= aConfig.mKnownFeasibleBSize - 1) {
       // aConfig.mKnownFeasibleBSize is where we want to be