Pass format as argument to getContentBitmapAsync.

content/browser/android/content_view_core_impl.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/android/content_view_core_impl.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 622 matching lines @@
       env, obj.obj(), static_cast<jint>(x_dip * dpi_scale()),
       static_cast<jint>(y_dip * dpi_scale()));
 }
 
 void ContentViewCoreImpl::GetScaledContentBitmap(
     float scale,
     SkColorType color_type,
     gfx::Rect src_subrect,
     ReadbackRequestCallback& result_callback) {
   RenderWidgetHostViewAndroid* view = GetRenderWidgetHostViewAndroid();
-  if (!view) {
+  if (!view || color_type == kUnknown_SkColorType) {
     result_callback.Run(SkBitmap(), READBACK_FAILED);
     return;
   }
 
   view->GetScaledContentBitmap(scale, color_type, src_subrect,
       result_callback);
 }
 
 void ContentViewCoreImpl::StartContentIntent(const GURL& content_url) {
   JNIEnv* env = AttachCurrentThread();
@@ skipping 737 matching lines @@
     return NULL;
 
   return view->GetJavaObject().Release();
 }
 
 bool RegisterContentViewCore(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content