Support using OpenGL ES context on desktop

src/gpu/gl/iOS/SkNativeGLContext_iOS.mm

Index: src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
diff --git a/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm b/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
index a276fd05da697085a2e353d2166e3ecb78850ffe..1e11c0deb7be8afd32fdbf83314f6b9b6d4717c0 100644
--- a/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
+++ b/src/gpu/gl/iOS/SkNativeGLContext_iOS.mm
@@ -42,7 +42,11 @@ void SkNativeGLContext::destroyGLContext() {
     [EAGLCTX release];
 }
 
-const GrGLInterface* SkNativeGLContext::createGLContext() {
+const GrGLInterface* SkNativeGLContext::createGLContext(GrGLStandard forcedGpuAPI) {
+    if (kGL_GrGLStandard == forcedGpuAPI) {
+        return NULL;
+    }
+
     fEAGLContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
     [EAGLContext setCurrentContext:EAGLCTX];
     
@@ -61,4 +65,4 @@ void SkNativeGLContext::makeCurrent() const {
     }
 }
 
-void SkNativeGLContext::swapBuffers() const { }
+void SkNativeGLContext::swapBuffers() const { }