Move common distiller code to superclass

This change moves any code related to JavaScript and HTML generation
in dom distiller to a superclass that all platforms can use.

BUG=472797

Review URL: https://codereview.chromium.org/1101993003

Cr-Commit-Position: refs/heads/master@{#327055}

components/dom_distiller.gypi

@@ -82,6 +82,8 @@
         'dom_distiller/core/dom_distiller_model.cc',
         'dom_distiller/core/dom_distiller_model.h',
         'dom_distiller/core/dom_distiller_observer.h',
+        'dom_distiller/core/dom_distiller_request_view_base.cc',
+        'dom_distiller/core/dom_distiller_request_view_base.h',
         'dom_distiller/core/dom_distiller_service.cc',
         'dom_distiller/core/dom_distiller_service.h',
         'dom_distiller/core/dom_distiller_service_android.cc',

components/dom_distiller/core/BUILD.gn

@@ -32,6 +32,8 @@ source_set("core") {
     "dom_distiller_model.cc",
     "dom_distiller_model.h",
     "dom_distiller_observer.h",
+    "dom_distiller_request_view_base.cc",
+    "dom_distiller_request_view_base.h",
     "dom_distiller_service.cc",
     "dom_distiller_service.h",
     "dom_distiller_store.cc",

components/dom_distiller/core/dom_distiller_request_view_base.cc

+// Copyright 2015 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 "components/dom_distiller/core/dom_distiller_request_view_base.h"
+
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/dom_distiller/core/distilled_page_prefs.h"
+#include "components/dom_distiller/core/dom_distiller_service.h"
+#include "components/dom_distiller/core/task_tracker.h"
+#include "components/dom_distiller/core/url_constants.h"
+#include "components/dom_distiller/core/viewer.h"
+#include "content/public/browser/navigation_details.h"
+#include "content/public/browser/navigation_entry.h"
+#include "content/public/browser/url_data_source.h"
+#include "net/base/url_util.h"
+#include "net/url_request/url_request.h"
+
+namespace dom_distiller {
+
+DomDistillerRequestViewBase::DomDistillerRequestViewBase(
+    scoped_ptr<DistillerDataCallback> callback,
+    DistilledPagePrefs* distilled_page_prefs)
+    : callback_(callback.Pass()),
+      page_count_(0),
+      distilled_page_prefs_(distilled_page_prefs),
+      is_error_page_(false) {
+}
+
+DomDistillerRequestViewBase::~DomDistillerRequestViewBase() {
+}
+
+void DomDistillerRequestViewBase::FlagAsErrorPage() {
+  is_error_page_ = true;
+  std::string error_page_html =
+      viewer::GetErrorPageHtml(distilled_page_prefs_->GetTheme(),
+                               distilled_page_prefs_->GetFontFamily());
+  callback_->RunCallback(error_page_html);
+}
+
+bool DomDistillerRequestViewBase::IsErrorPage() {
+  return is_error_page_;
+}
+
+void DomDistillerRequestViewBase::OnArticleReady(
+    const DistilledArticleProto* article_proto) {
+  if (page_count_ == 0) {
+    std::string unsafe_page_html = viewer::GetUnsafeArticleTemplateHtml(
+        &article_proto->pages(0), distilled_page_prefs_->GetTheme(),
+        distilled_page_prefs_->GetFontFamily());
+    callback_->RunCallback(unsafe_page_html);
+    // Send first page to client.
+    SendJavaScript(viewer::GetUnsafeArticleContentJs(article_proto));
+    // If any content was loaded, show the feedback form.
+    SendJavaScript(viewer::GetShowFeedbackFormJs());
+  } else if (page_count_ == article_proto->pages_size()) {
+    // We may still be showing the "Loading" indicator.
+    SendJavaScript(viewer::GetToggleLoadingIndicatorJs(true));
+  } else {
+    // It's possible that we didn't get some incremental updates from the
+    // distiller. Ensure all remaining pages are flushed to the viewer.
+    for (; page_count_ < article_proto->pages_size(); page_count_++) {
+      const DistilledPageProto& page = article_proto->pages(page_count_);
+      SendJavaScript(viewer::GetUnsafeIncrementalDistilledPageJs(
+          &page, page_count_ == article_proto->pages_size()));
+    }
+  }
+  // No need to hold on to the ViewerHandle now that distillation is complete.
+  viewer_handle_.reset();
+}
+
+void DomDistillerRequestViewBase::OnArticleUpdated(
+    ArticleDistillationUpdate article_update) {
+  for (; page_count_ < static_cast<int>(article_update.GetPagesSize());
+       page_count_++) {
+    const DistilledPageProto& page =
+        article_update.GetDistilledPage(page_count_);
+    // Send the page content to the client. This will execute after the page is
+    // ready.
+    SendJavaScript(viewer::GetUnsafeIncrementalDistilledPageJs(&page, false));
+
+    if (page_count_ == 0) {
+      // This is the first page, so send Viewer page scaffolding too.
+      std::string unsafe_page_html = viewer::GetUnsafeArticleTemplateHtml(
+          &page, distilled_page_prefs_->GetTheme(),
+          distilled_page_prefs_->GetFontFamily());
+      callback_->RunCallback(unsafe_page_html);
+      // If any content was loaded, show the feedback form.
+      SendJavaScript(viewer::GetShowFeedbackFormJs());
+    }
+  }
+}
+
+void DomDistillerRequestViewBase::OnChangeTheme(
+    DistilledPagePrefs::Theme new_theme) {
+  SendJavaScript(viewer::GetDistilledPageThemeJs(new_theme));
+}
+
+void DomDistillerRequestViewBase::OnChangeFontFamily(
+    DistilledPagePrefs::FontFamily new_font) {
+  SendJavaScript(viewer::GetDistilledPageFontFamilyJs(new_font));
+}
+
+void DomDistillerRequestViewBase::TakeViewerHandle(
+    scoped_ptr<ViewerHandle> viewer_handle) {
+  viewer_handle_ = viewer_handle.Pass();
+}
+
+}  // namespace dom_distiller

components/dom_distiller/core/dom_distiller_request_view_base.h

+// Copyright 2015 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_DOM_DISTILLER_REQUEST_VIEW_BASE_H_
+#define COMPONENTS_DOM_DISTILLER_CORE_DOM_DISTILLER_REQUEST_VIEW_BASE_H_
+
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/utf_string_conversions.h"
+#include "components/dom_distiller/core/distilled_page_prefs.h"
+#include "components/dom_distiller/core/dom_distiller_service.h"
+#include "components/dom_distiller/core/task_tracker.h"
+#include "components/dom_distiller/core/viewer.h"
+#include "content/public/browser/url_data_source.h"
+#include "net/base/url_util.h"
+
+namespace dom_distiller {
+
+// This interface is used to abstract the data callback from the distiller. The
+// callbacks for different platforms have different numbers of parameters
+// (namely iOS and Android) which makes this necessary.
+class DistillerDataCallback {
+ public:
+  virtual ~DistillerDataCallback(){};
+  virtual void RunCallback(std::string& data) = 0;
+};
+
+// Handles receiving data asynchronously for a specific entry, and passing
+// it along to the data callback for the data source. Lifetime matches that of
+// the current main frame's page in the Viewer instance.
+class DomDistillerRequestViewBase
+    : public ViewRequestDelegate,
+      public DistilledPagePrefs::Observer {
+ public:
+  explicit DomDistillerRequestViewBase(
+      scoped_ptr<DistillerDataCallback> callback,
+      DistilledPagePrefs* distilled_page_prefs);
+  ~DomDistillerRequestViewBase() override;
+
+  // Flag this request as an error and send the error page template.
+  void FlagAsErrorPage();
+  // Get if this viewer is in an error state.
+  bool IsErrorPage();
+
+  // ViewRequestDelegate implementation:
+  void OnArticleReady(const DistilledArticleProto* article_proto) override;
+
+  void OnArticleUpdated(ArticleDistillationUpdate article_update) override;
+
+  void TakeViewerHandle(scoped_ptr<ViewerHandle> viewer_handle);
+
+ protected:
+  // DistilledPagePrefs::Observer implementation:
+  void OnChangeFontFamily(
+      DistilledPagePrefs::FontFamily new_font_family) override;
+  void OnChangeTheme(DistilledPagePrefs::Theme new_theme) override;
+
+  // Sends JavaScript to the attached Viewer, buffering data if the viewer isn't
+  // ready.
+  virtual void SendJavaScript(const std::string& buffer) = 0;
+
+  // The handle to the view request towards the DomDistillerService. It
+  // needs to be kept around to ensure the distillation request finishes.
+  scoped_ptr<ViewerHandle> viewer_handle_;
+
+  // Holds the callback to where the data retrieved is sent back.
+  scoped_ptr<DistillerDataCallback> callback_;
+
+  // Number of pages of the distilled article content that have been rendered by
+  // the viewer.
+  int page_count_;
+
+  // Interface for accessing preferences for distilled pages.
+  DistilledPagePrefs* distilled_page_prefs_;
+
+  // Flag to tell this observer that the web contents are in an error state.
+  bool is_error_page_;
+};
+
+}  // namespace dom_distiller
+
+#endif  // COMPONENTS_DOM_DISTILLER_CORE_DOM_DISTILLER_REQUEST_VIEW_BASE_H_