Add basic initialization code for ContextNULL so it can run some tests.

BUG=angleproject:1468

Change-Id: I8dfc9a3c71e5638de22bc9d9a5dadfb495ef23a7
Reviewed-on: https://chromium-review.googlesource.com/388846
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/renderer/null/FramebufferNULL.cpp b/src/libANGLE/renderer/null/FramebufferNULL.cpp
index cedea8e..91d3314 100644
--- a/src/libANGLE/renderer/null/FramebufferNULL.cpp
+++ b/src/libANGLE/renderer/null/FramebufferNULL.cpp
@@ -26,28 +26,24 @@
 
 gl::Error FramebufferNULL::discard(size_t count, const GLenum *attachments)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::invalidate(size_t count, const GLenum *attachments)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::invalidateSub(size_t count,
                                          const GLenum *attachments,
                                          const gl::Rectangle &area)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::clear(ContextImpl *context, GLbitfield mask)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::clearBufferfv(ContextImpl *context,
@@ -55,8 +51,7 @@
                                          GLint drawbuffer,
                                          const GLfloat *values)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::clearBufferuiv(ContextImpl *context,
@@ -64,8 +59,7 @@
                                           GLint drawbuffer,
                                           const GLuint *values)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::clearBufferiv(ContextImpl *context,
@@ -73,8 +67,7 @@
                                          GLint drawbuffer,
                                          const GLint *values)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::clearBufferfi(ContextImpl *context,
@@ -83,8 +76,7 @@
                                          GLfloat depth,
                                          GLint stencil)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 GLenum FramebufferNULL::getImplementationColorReadFormat() const
@@ -119,8 +111,7 @@
                                       GLenum type,
                                       GLvoid *pixels) const
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 gl::Error FramebufferNULL::blit(ContextImpl *context,
@@ -129,19 +120,16 @@
                                 GLbitfield mask,
                                 GLenum filter)
 {
-    UNIMPLEMENTED();
-    return gl::Error(GL_INVALID_OPERATION);
+    return gl::NoError();
 }
 
 bool FramebufferNULL::checkStatus() const
 {
-    UNIMPLEMENTED();
-    return bool();
+    return true;
 }
 
 void FramebufferNULL::syncState(const gl::Framebuffer::DirtyBits &dirtyBits)
 {
-    UNIMPLEMENTED();
 }
 
 }  // namespace rx