Add decode() functionality to image elements.

third_party/WebKit/Source/core/page/ChromeClient.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple, Inc. All rights
  * reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 332 matching lines @@
       BlameContext*) = 0;
 
   // Returns the time of the beginning of the last beginFrame, in seconds, if
   // any, and 0.0 otherwise.
   virtual double LastFrameTimeMonotonic() const { return 0.0; }
 
   virtual void InstallSupplements(LocalFrame&) {}
 
   virtual WebLayerTreeView* GetWebLayerTreeView(LocalFrame*) { return nullptr; }
 
+  virtual void RequestDecode(
+      LocalFrame*,
+      sk_sp<SkImage> image,
+      std::unique_ptr<WTF::Function<void(bool)>> callback) {
+    (*callback)(false);
+  }
+
   DECLARE_TRACE();
 
  protected:
   ~ChromeClient() override {}
 
   virtual void ShowMouseOverURL(const HitTestResult&) = 0;
   virtual void SetWindowRect(const IntRect&, LocalFrame&) = 0;
   virtual bool OpenBeforeUnloadConfirmPanelDelegate(LocalFrame*,
                                                     bool is_reload) = 0;
   virtual bool OpenJavaScriptAlertDelegate(LocalFrame*, const String&) = 0;
@@ skipping 13 matching lines @@
   WeakMember<Node> last_mouse_over_node_;
   LayoutPoint last_tool_tip_point_;
   String last_tool_tip_text_;
 
   FRIEND_TEST_ALL_PREFIXES(ChromeClientTest, SetToolTipFlood);
 };
 
 }  // namespace blink
 
 #endif  // ChromeClient_h