Support error handling for Surface readbacks

content/public/browser/render_widget_host.h

Index: content/public/browser/render_widget_host.h
diff --git a/content/public/browser/render_widget_host.h b/content/public/browser/render_widget_host.h
index e37c3cdce5ef35e225d8b5aca937dad481e7b584..efc59ff3eb167f82a16e0bd04f5f426cf97f536b 100644
--- a/content/public/browser/render_widget_host.h
+++ b/content/public/browser/render_widget_host.h
@@ -8,6 +8,7 @@
 #include "base/callback.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/native_web_keyboard_event.h"
+#include "content/public/browser/readback_types.h"
 #include "ipc/ipc_channel.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
@@ -177,11 +178,10 @@ class CONTENT_EXPORT RenderWidgetHost : public IPC::Sender {
   // NOTE: |callback| is called synchronously if the backing store is available.
   // When accelerated compositing is active, |callback| may be called
   // asynchronously.
-  virtual void CopyFromBackingStore(
-      const gfx::Rect& src_rect,
-      const gfx::Size& accelerated_dst_size,
-      const base::Callback<void(bool, const SkBitmap&)>& callback,
-      const SkColorType color_type) = 0;
+  virtual void CopyFromBackingStore(const gfx::Rect& src_rect,
+                                    const gfx::Size& accelerated_dst_size,
+                                    ReadbackRequestCallback& callback,
+                                    const SkColorType color_type) = 0;
   // Ensures that the view does not drop the backing store even when hidden.
   virtual bool CanCopyFromBackingStore() = 0;
 #if defined(OS_ANDROID)