WebGLCompat: Fix depthstencil query results.

getFramebufferAttachmentParameter returns incorrect
result for framebuffers in an inconsistent state.

BUG=angleproject:2259

Change-Id: I76fa99f1b8847c30469d344bd93dedd9cf6657bf
Reviewed-on: https://chromium-review.googlesource.com/798318
Reviewed-by: Bryan Bernhart <bryan.bernhart@intel.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index caebc20..18a2c3b 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -1686,7 +1686,7 @@
                                                   GLint *params)
 {
     const Framebuffer *framebuffer = mGLState.getTargetFramebuffer(target);
-    QueryFramebufferAttachmentParameteriv(framebuffer, attachment, pname, params);
+    QueryFramebufferAttachmentParameteriv(this, framebuffer, attachment, pname, params);
 }
 
 void Context::getRenderbufferParameteriv(GLenum target, GLenum pname, GLint *params)
@@ -2220,7 +2220,7 @@
         return EGL_NONE;
     }
 
-    const FramebufferAttachment *backAttachment = framebuffer->getAttachment(GL_BACK);
+    const FramebufferAttachment *backAttachment = framebuffer->getAttachment(this, GL_BACK);
     ASSERT(backAttachment != nullptr);
     return backAttachment->getSurface()->getRenderBuffer();
 }