Bug 1315383 part 3 - [css-grid] Don't try to preserve intrinsic ratio when applying min/max-size, if either axis has 'stretch' alignment. r=dholbert

layout/generic/nsFrame.cpp

@@ -5224,7 +5224,13 @@ nsFrame::ComputeSizeWithIntrinsicDimensions(nsRenderingContext*  aRenderingConte
             tentISize = NSCoordMulDiv(bSize, logicalRatio.ISize(aWM), logicalRatio.BSize(aWM));
           }
         }
+      }
 
+      // ComputeAutoSizeWithIntrinsicDimensions preserves the ratio when applying
+      // the min/max-size.  We don't want that when we have 'stretch' in either
+      // axis because tentISize/tentBSize is likely not according to ratio now.
+      if (aIntrinsicRatio != nsSize(0, 0) &&
+          stretchI != eStretch && stretchB != eStretch) {
         nsSize autoSize = nsLayoutUtils::
           ComputeAutoSizeWithIntrinsicDimensions(minISize, minBSize,
                                                  maxISize, maxBSize,
@@ -5236,11 +5242,7 @@ nsFrame::ComputeSizeWithIntrinsicDimensions(nsRenderingContext*  aRenderingConte
         iSize = autoSize.width;
         bSize = autoSize.height;
       } else {
-        // No intrinsic ratio, so just clamp the dimensions
-        // independently without calling
-        // ComputeAutoSizeWithIntrinsicDimensions, which deals with
-        // propagating these changes to the other dimension (and would
-        // be incorrect when there is no intrinsic ratio).
+        // Not honoring an intrinsic ratio: clamp the dimensions independently.
         iSize = NS_CSS_MINMAX(tentISize, minISize, maxISize);
         bSize = NS_CSS_MINMAX(tentBSize, minBSize, maxBSize);
       }