Return an Error from Framebuffer::syncState.

This pipes errors up from the Impl to the top level. There are
still a few places were error swallowing is needed, because the
Framebuffer API doesn't support returning an error.

Bug: angleproject:2372
Change-Id: Idc06bda1817fd28075940f69874d8b6ba69194f9
Reviewed-on: https://chromium-review.googlesource.com/954290
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Luc Ferron <lucferron@chromium.org>
diff --git a/src/libANGLE/State.cpp b/src/libANGLE/State.cpp
index 66873aa..2fe3294 100644
--- a/src/libANGLE/State.cpp
+++ b/src/libANGLE/State.cpp
@@ -2243,11 +2243,11 @@
         {
             case DIRTY_OBJECT_READ_FRAMEBUFFER:
                 ASSERT(mReadFramebuffer);
-                mReadFramebuffer->syncState(context);
+                ANGLE_TRY(mReadFramebuffer->syncState(context));
                 break;
             case DIRTY_OBJECT_DRAW_FRAMEBUFFER:
                 ASSERT(mDrawFramebuffer);
-                mDrawFramebuffer->syncState(context);
+                ANGLE_TRY(mDrawFramebuffer->syncState(context));
                 break;
             case DIRTY_OBJECT_VERTEX_ARRAY:
                 ASSERT(mVertexArray);