#493: image max-width M823483 M1247929

layout/base/nsLayoutUtils.cpp

@@ -4489,6 +4489,43 @@ GetIntrinsicCoord(const nsStyleCoord& aStyle,
 static int32_t gNoiseIndent = 0;
 #endif
 
+// Return true for form controls whose minimum intrinsic inline-size
+// shrinks to 0 when they have a percentage inline-size (but not
+// percentage max-inline-size).  (Proper replaced elements, whose
+// intrinsic minimium inline-size shrinks to 0 for both percentage
+// inline-size and percentage max-inline-size, are handled elsewhere.)
+inline static bool
+FormControlShrinksForPercentISize(nsIFrame* aFrame)
+{
+  if (!aFrame->IsFrameOfType(nsIFrame::eReplaced)) {
+    // Quick test to reject most frames.
+    return false;
+  }
+
+  nsIAtom* fType = aFrame->GetType();
+  if (fType == nsGkAtoms::meterFrame || fType == nsGkAtoms::progressFrame) {
+    // progress and meter do have this shrinking behavior
+    // FIXME: Maybe these should be nsIFormControlFrame?
+    return true;
+  }
+
+  if (!static_cast<nsIFormControlFrame*>(do_QueryFrame(aFrame))) {
+    // Not a form control.  This includes fieldsets, which do not
+    // shrink.
+    return false;
+  }
+
+  if (fType == nsGkAtoms::gfxButtonControlFrame ||
+      fType == nsGkAtoms::HTMLButtonControlFrame) {
+    // Buttons don't have this shrinking behavior.  (Note that color
+    // inputs do, even though they inherit from button, so we can't use
+    // do_QueryFrame here.)
+    return false;
+  }
+
+  return true;
+}
+
 /**
  * Add aOffsets which describes what to add on outside of the content box
  * aContentSize (controlled by 'box-sizing') and apply min/max properties.
@@ -4565,19 +4602,23 @@ AddIntrinsicSizeOffset(nsRenderingContext* aRenderingContext,
   pctTotal += pctOutsideSize;
 
   nscoord size;
-  if (GetAbsoluteCoord(aStyleSize, size) ||
-      GetIntrinsicCoord(aStyleSize, aRenderingContext, aFrame,
-                        PROP_WIDTH, size)) {
+  if (aType == nsLayoutUtils::MIN_ISIZE &&
+      (((aStyleSize.HasPercent() || aStyleMaxSize.HasPercent()) &&
+        aFrame->IsFrameOfType(nsIFrame::eReplacedSizing)) ||
+       (aStyleSize.HasPercent() &&
+        FormControlShrinksForPercentISize(aFrame)))) {
+    // A percentage width or max-width on replaced elements means they
+    // can shrink to 0.
+    // This is also true for percentage widths (but not max-widths) on
+    // text inputs.
+    // Note that if this is max-width, this overrides the fixed-width
+    // rule in the next condition.
+    result = 0; // let |min| handle padding/border/margin
+  } else if (GetAbsoluteCoord(aStyleSize, size) ||
+             GetIntrinsicCoord(aStyleSize, aRenderingContext, aFrame,
+                               PROP_WIDTH, size)) {
     result = nsLayoutUtils::AddPercents(aType, size + coordOutsideSize,
                                         pctOutsideSize);
-  } else if (aType == nsLayoutUtils::MIN_ISIZE &&
-             // The only cases of coord-percent-calc() units that
-             // GetAbsoluteCoord didn't handle are percent and calc()s
-             // containing percent.
-             aStyleSize.IsCoordPercentCalcUnit() &&
-             aFrame->IsFrameOfType(nsIFrame::eReplaced)) {
-    // A percentage width on replaced elements means they can shrink to 0.
-    result = 0; // let |min| handle padding/border/margin
   } else {
     // NOTE: We could really do a lot better for percents and for some
     // cases of calc() containing percent (certainly including any where