Make SetSwapInterval a log warning rather than a notreached.

TBR=apatrick@chromium.org

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@86749 0039d316-1c4b-4281-b951-d872f2087c98

ui/gfx/gl/gl_context_cgl.cc

@@ -102,7 +102,7 @@ void* GLContextCGL::GetHandle() {
 
 void GLContextCGL::SetSwapInterval(int interval) {
   DCHECK(IsCurrent(NULL));
-  NOTREACHED() << "Attempt to call SetSwapInterval on a GLContextCGL.";
+  LOG(WARNING) << "GLContex: GLContextCGL::SetSwapInterval is ignored.";
 }
 
 }  // namespace gfx

ui/gfx/gl/gl_context_osmesa.cc

@@ -102,7 +102,7 @@ void* GLContextOSMesa::GetHandle() {
 
 void GLContextOSMesa::SetSwapInterval(int interval) {
   DCHECK(IsCurrent(NULL));
-  NOTREACHED() << "Attempt to call SetSwapInterval on an GLContextOSMesa.";
+  LOG(WARNING) << "GLContextOSMesa::SetSwapInterval is ignored.";
 }
 
 }  // namespace gfx

ui/gfx/gl/gl_context_wgl.cc

@@ -111,6 +111,10 @@ void GLContextWGL::SetSwapInterval(int interval) {
   DCHECK(IsCurrent(NULL));
   if (HasExtension("WGL_EXT_swap_control") && wglSwapIntervalEXT) {
     wglSwapIntervalEXT(interval);
+  } else {
+      LOG(WARNING) <<
+          "Could not disable vsync: driver does not "
+          "support WGL_EXT_swap_control";
   }
 }