[dom_distiller] Add support for incremental viewer.

components/dom_distiller/core/viewer.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_DOM_DISTILLER_CORE_VIEWER_H_
 #define COMPONENTS_DOM_DISTILLER_CORE_VIEWER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/strings/string16.h"
 
 namespace dom_distiller {
 
 class DistilledArticleProto;
+class DistilledPageProto;
 class DomDistillerServiceInterface;
 class ViewerHandle;
 class ViewRequestDelegate;
 
 namespace viewer {
 
 // Returns a full HTML page based on the given |article_proto|. This is supposed
-// to displayed to the end user. The returned HTML should be considered unsafe,
-// so callers must ensure rendering it does not compromise Chrome.
-const std::string GetUnsafeHtml(const DistilledArticleProto* article_proto);
+// to be displayed to the end user. The returned HTML should be considered
+// unsafe, so callers must ensure rendering it does not compromise Chrome.
+const std::string GetUnsafeArticleHtml(
+    const DistilledArticleProto* article_proto);
+
+// Returns the base Viewer HTML page based on the given |page_proto|. This is
+// supposed to be displayed to the end user. The returned HTML should be
+// considered unsafe, so callers must ensure rendering it does not compromise
+// Chrome. The difference from |GetUnsafeArticleHtml| is that this can be used
+// for displaying an in-flight distillation instead of waiting for the full
+// article.
+const std::string GetUnsafePartialArticleHtml(
+    const DistilledPageProto* page_proto);
+
+// Returns a JavaScript blob for updating a partial view request with additional
+// distilled content. Meant for use when viewing a slow or long multi-page
+// article. |is_last_page| indicates whether this is the last page of the
+// article.
+const std::string GetUnsafeIncrementalDistilledPageJs(
+    const DistilledPageProto* page_proto,
+    const bool is_last_page);
+
+// Returns a JavaScript blob for controlling the "in-progress" indicator when
+// viewing a partially-distilled page. |is_last_page| indicates whether this is
+// the last page of the article (i.e. loading indicator should be removed).
+const std::string GetToggleLoadingIndicatorJs(const bool is_last_page);
 
 // Returns a full HTML page which displays a generic error.
 const std::string GetErrorPageHtml();
 
 // Returns the default CSS to be used for a viewer.
 const std::string GetCss();
 
+// Returns the default JS to be used for a viewer.
+const std::string GetJavaScript();
+
 // Based on the given path, calls into the DomDistillerServiceInterface for
 // viewing distilled content based on the |path|.
 scoped_ptr<ViewerHandle> CreateViewRequest(
     DomDistillerServiceInterface* dom_distiller_service,
     const std::string& path,
     ViewRequestDelegate* view_request_delegate);
 
 }  // namespace viewer
 
 }  // namespace dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_CORE_VIEWER_H_