Remove "GLContex: GLContextCGL::SetSwapInterval is ignored" spam

This message fills up about:gpu and stdout, and doesn't provide any
value.

BUG=

Review URL: https://codereview.chromium.org/645143002

Cr-Commit-Position: refs/heads/master@{#299169}

ui/gl/gl_context_cgl.cc

@@ -232,10 +232,8 @@ void* GLContextCGL::GetHandle() {
 
 void GLContextCGL::SetSwapInterval(int interval) {
   DCHECK(IsCurrent(NULL));
-  LOG(WARNING) << "GLContex: GLContextCGL::SetSwapInterval is ignored.";
 }
 
-
 bool GLContextCGL::GetTotalGpuMemory(size_t* bytes) {
   DCHECK(bytes);
   *bytes = 0;