libvpx: Pull from upstream

source/libvpx/test/external_frame_buffer_test.cc

Index: source/libvpx/test/external_frame_buffer_test.cc
diff --git a/source/libvpx/test/external_frame_buffer_test.cc b/source/libvpx/test/external_frame_buffer_test.cc
index 70b3009289188e4717032af80c3219a14259b99c..d02dca2be86c3bd0045b94baba3a2eadaed11786 100644
--- a/source/libvpx/test/external_frame_buffer_test.cc
+++ b/source/libvpx/test/external_frame_buffer_test.cc
@@ -97,13 +97,19 @@ class ExternalFrameBufferList {
     return 0;
   }
 
-  // Marks the external frame buffer that |fb| is pointing too as free.
+  // Marks the external frame buffer that |fb| is pointing to as free.
   // Returns < 0 on an error.
   int ReturnFrameBuffer(vpx_codec_frame_buffer_t *fb) {
-    EXPECT_TRUE(fb != NULL);
+    if (fb == NULL) {
+      EXPECT_TRUE(fb != NULL);
+      return -1;
+    }
     ExternalFrameBuffer *const ext_fb =
         reinterpret_cast<ExternalFrameBuffer*>(fb->priv);
-    EXPECT_TRUE(ext_fb != NULL);
+    if (ext_fb == NULL) {
+      EXPECT_TRUE(ext_fb != NULL);
+      return -1;
+    }
     EXPECT_EQ(1, ext_fb->in_use);
     ext_fb->in_use = 0;
     return 0;