[css-grid] Add coverage for min-height behavior

LayoutTests/fast/css-grid-layout/min-width-height-auto.html

Index: LayoutTests/fast/css-grid-layout/min-width-height-auto.html
diff --git a/LayoutTests/fast/css-grid-layout/min-width-height-auto.html b/LayoutTests/fast/css-grid-layout/min-width-height-auto.html
index 5111c5e2e4832d8812e328f4e82d70fed5e66468..604544b8382b59e62769a440cf02a1930a1ba66f 100644
--- a/LayoutTests/fast/css-grid-layout/min-width-height-auto.html
+++ b/LayoutTests/fast/css-grid-layout/min-width-height-auto.html
@@ -37,6 +37,7 @@
 }
 
 .noStretch {
+    align-items: start;
     justify-items: start;
 }
 </style>
@@ -84,7 +85,7 @@
 
 <div class="container">
     <div class="grid noStretch">
-        <div class="ahem minSmaller" data-expected-width="100" data-expected-height="10">XXXX</div>
+        <div class="ahem minSmaller" data-expected-width="100" data-expected-height="25">XXXX</div>

[svillar, 2015/09/03 13:24:36]

Although adding more test cases is nice I don't get why setting a min-height was
forcing the item to be 10px height before your change. That means that we have a
bug there because in the test just above this one, the item is 25px height so
setting a min-height must not shrink the item.

[Manuel Rego, 2015/09/04 13:59:17]

Yeah, I agree this is weird, but per spec the item can stretch or shrink when
using "stretch":
https://drafts.csswg.org/css-align/#stretch

Shrink doesn't happen usually because of the default "min-widht|height: auto;".

I've added more info in the bug regarding this for future reference:
https://code.google.com/p/chromium/issues/detail?id=510061#c5

     </div>
 </div>