Add decode() functionality to image elements.

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

Index: third_party/WebKit/Source/core/page/ChromeClient.h
diff --git a/third_party/WebKit/Source/core/page/ChromeClient.h b/third_party/WebKit/Source/core/page/ChromeClient.h
index de24ec369655edf13c0c0d53ecffe4c2a9b1e6b1..21a903d687218a92af7101806a29310c8e1c1d75 100644
--- a/third_party/WebKit/Source/core/page/ChromeClient.h
+++ b/third_party/WebKit/Source/core/page/ChromeClient.h
@@ -372,6 +372,13 @@ class CORE_EXPORT ChromeClient : public PlatformChromeClient {
     return nullptr;
   }
 
+  virtual void RequestDecode(
+      LocalFrame*,
+      sk_sp<SkImage> image,
+      std::unique_ptr<WTF::Function<void(bool)>> callback) {
+    (*callback)(false);
+  }
+
   DECLARE_TRACE();
 
  protected: