Add BlimpDocument, pull out functions in BlimpCompositor.

blimp/client/test/render_widget/mock_render_widget_feature.cc

Index: blimp/client/test/render_widget/mock_render_widget_feature.cc
diff --git a/blimp/client/core/contents/mock_ime_feature_delegate.cc b/blimp/client/test/render_widget/mock_render_widget_feature.cc
similarity index 50%
copy from blimp/client/core/contents/mock_ime_feature_delegate.cc
copy to blimp/client/test/render_widget/mock_render_widget_feature.cc
index eeefb278a94e5a552e1896ae622987fa857b6c7a..43e9df9451bd31a0e4f4b2920c1353ef248786fe 100644
--- a/blimp/client/core/contents/mock_ime_feature_delegate.cc
+++ b/blimp/client/test/render_widget/mock_render_widget_feature.cc
@@ -2,17 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "blimp/client/core/contents/mock_ime_feature_delegate.h"
-
-#include "third_party/skia/include/core/SkBitmap.h"
-#include "url/gurl.h"
+#include "blimp/client/test/render_widget/mock_render_widget_feature.h"
 
 namespace blimp {
 namespace client {
 
-MockImeFeatureDelegate::MockImeFeatureDelegate() {}
+MockRenderWidgetFeature::MockRenderWidgetFeature() = default;
 
-MockImeFeatureDelegate::~MockImeFeatureDelegate() {}
+MockRenderWidgetFeature::~MockRenderWidgetFeature() = default;
 
 }  // namespace client
 }  // namespace blimp