Reset scissor reset before presenting in opengl

The opengl backend uses glBlitFramebuffer to present frames which
is affected by the opengl scissor rect.

Bug: dawn:616
Change-Id: I0b8c3eb7139ab22a98eeb60e3ad16678e3afad5d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/37101
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>
Commit-Queue: Mark Sibly <marksibly@gmail.com>
diff --git a/src/dawn_native/opengl/NativeSwapChainImplGL.cpp b/src/dawn_native/opengl/NativeSwapChainImplGL.cpp
index 3cfdad4..330999d 100644
--- a/src/dawn_native/opengl/NativeSwapChainImplGL.cpp
+++ b/src/dawn_native/opengl/NativeSwapChainImplGL.cpp
@@ -72,6 +72,7 @@
         const OpenGLFunctions& gl = mDevice->gl;
         gl.BindFramebuffer(GL_READ_FRAMEBUFFER, mBackFBO);
         gl.BindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+        gl.Scissor(0, 0, mWidth, mHeight);
         gl.BlitFramebuffer(0, 0, mWidth, mHeight, 0, mHeight, mWidth, 0, GL_COLOR_BUFFER_BIT,
                            GL_NEAREST);