Fix screen mirroring on Chrome OS (ReflectorTexture partial swap)

content/browser/compositor/reflector_texture.h

Index: content/browser/compositor/reflector_texture.h
diff --git a/content/browser/compositor/reflector_texture.h b/content/browser/compositor/reflector_texture.h
index 197399b37ac11b57672511353145b98eddac7fed..37dcdd3512bae1ff5f4620d4feab166d3ab5ab2d 100644
--- a/content/browser/compositor/reflector_texture.h
+++ b/content/browser/compositor/reflector_texture.h
@@ -38,6 +38,8 @@ class CONTENT_EXPORT ReflectorTexture {
   void CopyTextureFullImage(const gfx::Size& size);
   void CopyTextureSubImage(const gfx::Rect& size);
 
+  bool is_texture_defined() const { return is_texture_defined_; }
+
   uint32_t texture_id() const { return texture_id_; }
   scoped_refptr<OwnedMailbox> mailbox() { return mailbox_; }
 
@@ -45,6 +47,7 @@ class CONTENT_EXPORT ReflectorTexture {
   scoped_refptr<OwnedMailbox> mailbox_;
   std::unique_ptr<display_compositor::GLHelper> gl_helper_;
   uint32_t texture_id_;
+  bool is_texture_defined_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(ReflectorTexture);
 };