Don't assert if glCheckFramebufferStatus fails

This can fail if the context has been reset or abandoned. Instead return
false so the caller print a warning message and skip rendering.

Bug: chromium:1235232
Bug: skia:12258
Bug: skia:5200
Change-Id: If78a914a25d09d48477e04317a34473632f76207
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/435816
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
Auto-Submit: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/gl/GrGLRenderTarget.cpp b/src/gpu/gl/GrGLRenderTarget.cpp
index ebfd20d..fd1716a 100644
--- a/src/gpu/gl/GrGLRenderTarget.cpp
+++ b/src/gpu/gl/GrGLRenderTarget.cpp
@@ -170,11 +170,12 @@
 
 #ifdef SK_DEBUG
     if (!gpu->glCaps().skipErrorChecks()) {
-        // This check can cause problems in Chromium if the context has been asynchronously
-        // abandoned (see skbug.com/5200)
         GrGLenum status;
         GR_GL_CALL_RET(interface, status, CheckFramebufferStatus(GR_GL_FRAMEBUFFER));
-        SkASSERT(GR_GL_FRAMEBUFFER_COMPLETE == status);
+        if (status != GR_GL_FRAMEBUFFER_COMPLETE) {
+            // This can fail if the context has been asynchronously abandoned (see skbug.com/5200).
+            return false;
+        }
     }
 #endif