Fix flaky LayerTreeHostCopyRequestTestDeleteTexture test.

cc/resources/video_resource_updater_unittest.cc

Index: cc/resources/video_resource_updater_unittest.cc
diff --git a/cc/resources/video_resource_updater_unittest.cc b/cc/resources/video_resource_updater_unittest.cc
index dce047cd523f382c989318a9bd421f9f2dc28710..4b54fbe759f3cfb2c014f880d73c6b21bc93418d 100644
--- a/cc/resources/video_resource_updater_unittest.cc
+++ b/cc/resources/video_resource_updater_unittest.cc
@@ -55,6 +55,11 @@ class WebGraphicsContext3DUploadCounter : public TestWebGraphicsContext3D {
     TestWebGraphicsContext3D::deleteTexture(texture);
   }
 
+  void deleteTextures(GLsizei count, const GLuint* ids) override {
+    created_texture_count_ -= count;
+    TestWebGraphicsContext3D::deleteTextures(count, ids);
+  }
+
   int UploadCount() { return upload_count_; }
   void ResetUploadCount() { upload_count_ = 0; }