[Oilpan] Remove a GC_PLUGIN_IGNORE

Source/modules/webgl/WebGLRenderingContextBase.cpp

Index: Source/modules/webgl/WebGLRenderingContextBase.cpp
diff --git a/Source/modules/webgl/WebGLRenderingContextBase.cpp b/Source/modules/webgl/WebGLRenderingContextBase.cpp
index 10b30857634a3da6fc0c43b4ec6c3f7d461e5f1e..a9ede5ea3e1fad3f3e31f6e32248d76f964687f0 100644
--- a/Source/modules/webgl/WebGLRenderingContextBase.cpp
+++ b/Source/modules/webgl/WebGLRenderingContextBase.cpp
@@ -1080,6 +1080,9 @@ WebGLRenderingContextBase::~WebGLRenderingContextBase()
     m_renderbufferBinding = nullptr;
     m_valuebufferBinding = nullptr;
 
+    // WebGLTexture shared objects will be detached and deleted
+    // m_contextGroup->removeContext(this), which will bring about deleteTexture() calls.
+    // We null these out to avoid accessing those members in deleteTexture().
     for (size_t i = 0; i < m_textureUnits.size(); ++i) {
         m_textureUnits[i].m_texture2DBinding = nullptr;
         m_textureUnits[i].m_textureCubeMapBinding = nullptr;