GeometryInterface: Enable GeometryInterfaces by default.

third_party/WebKit/Source/core/css/cssom/CSSMatrixComponent.idl

Index: third_party/WebKit/Source/core/css/cssom/CSSMatrixComponent.idl
diff --git a/third_party/WebKit/Source/core/css/cssom/CSSMatrixComponent.idl b/third_party/WebKit/Source/core/css/cssom/CSSMatrixComponent.idl
index 0852e980bc998ca034f57245ace8df589f12d916..824d3bfd495dec2b8e81c9abf1794368b8bd92ef 100644
--- a/third_party/WebKit/Source/core/css/cssom/CSSMatrixComponent.idl
+++ b/third_party/WebKit/Source/core/css/cssom/CSSMatrixComponent.idl
@@ -10,7 +10,6 @@
     Constructor(DOMMatrixReadOnly matrix),
     Exposed=(Window,PaintWorklet),
     RuntimeEnabled=CSSTypedOM,
-    RuntimeEnabled=GeometryInterfaces,

[foolip, 2017/06/19 11:46:59]

Why was this removed? I'm fine with removing the REF entirely, but as long as it
exists then bits like this should be retained.

[zino, 2017/06/19 16:32:52]

The CSSMatrixComponent had two runtime flags CSSTypedOM and GeometryInterfaces
for its constructor before this patch. BTW, The CSSTypedOM was still under
experimental flag but it could be exposed due to another one GeometryInterface
flag.

I guess that the flag have been added because the constructor of
CSSMatrixComponent takes DOMMatrixReadOnly.
But it's not correct I think. Even if we enable GeometryInterfaces, the
CSSMatrixComponent should still be behind its runtime flag.
So, I removed it. :)

 ] interface CSSMatrixComponent : CSSTransformComponent {
     attribute DOMMatrix matrix;
 };