Do not report some CSS errors for code valid in other browsers.

LayoutTests/inspector/console/console-css-warnings.html

Index: LayoutTests/inspector/console/console-css-warnings.html
diff --git a/LayoutTests/inspector/console/console-css-warnings.html b/LayoutTests/inspector/console/console-css-warnings.html
index 60a2753fcfd53fe1d8ac5d2fe18d1d13c439c039..668699424ceac9ee3d15eb5d981719a29825f528 100644
--- a/LayoutTests/inspector/console/console-css-warnings.html
+++ b/LayoutTests/inspector/console/console-css-warnings.html
@@ -75,7 +75,15 @@ x {
 
 x {
     background:         invalid-linear-gradient(top,rgba(0,0,0,0) 0,rgba(0,0,0,1) 100%)    ;
+    background:         linear-gradient(top,rgba(0,0,0,0) 0,rgba(0,0,0,1) 100%)    ;

[PhistucK, 2013/06/21 21:13:10]

This test is problematic. While linear-gradient is valid, the value for which
you test here is invalid (it should read "to top" instead of "top").
While the Developer Tools is not meant to be a general CSS validator, I think it
would be good to warn this broken value (even if only to promote standards
compliancy and help avoid future useless breakage). Is there any way to do it?
basically, maybe add another case for (regular expression)
linear-gradient[\s\t\n\r]*\([\s\t\n\r]*(top|bottom|left|right).

     background: IE-hack ignored \9  ;
+    background: IE-hack ignored \0 ;
+    background: IE-hack ignored\0/ ;
+    animation: 3s slidein;
+    font-size-adjust: none;
+    transform: translateZ(0);
+    user-select: none;
+    -webkit-text-size-adjust: 100%;
 }
 
 x, {
@@ -102,6 +110,8 @@ x, {
 @media %%%;
 
 @keyframes;
+@keyframes { }
+@-moz-keyframes { }
 
 @page;
 @page xxx;