blimp: Update page load status update indicator to use first paint.

blimp/engine/session/page_load_tracker.h

Index: blimp/engine/session/page_load_tracker.h
diff --git a/blimp/engine/session/page_load_tracker.h b/blimp/engine/session/page_load_tracker.h
new file mode 100644
index 0000000000000000000000000000000000000000..2a1d02c218af57bf587c1ca8e7cdbc6195057be3
--- /dev/null
+++ b/blimp/engine/session/page_load_tracker.h
@@ -0,0 +1,82 @@
+// Copyright 2016 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 BLIMP_ENGINE_SESSION_PAGE_LOAD_TRACKER_H_
+#define BLIMP_ENGINE_SESSION_PAGE_LOAD_TRACKER_H_
+
+#include "base/containers/small_map.h"
+#include "base/macros.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_widget_host.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace blimp {
+namespace engine {
+
+enum class PageLoadStatus { LOADING, LOADED };
+
+class PageLoadTrackerClient {
+ public:
+  virtual ~PageLoadTrackerClient() {}
+
+  // Called when a navigation status update should be sent to the client.
+  // |load_status| indicates the status of the navigation. An update with a
+  // |LOADING| value is sent each time a new navigation is initiated. This
+  // update will be followed by a |LOADED| value when the navigation either
+  // successfully finishes or fails.
+  virtual void SendPageLoadStatusUpdate(PageLoadStatus load_status) = 0;
+};
+
+// Tracks the page load status for a tab using load and paint notifications
+// from the renderer.
+class PageLoadTracker : public content::WebContentsObserver {
+ public:
+  explicit PageLoadTracker(content::WebContents* web_contents,
+                           PageLoadTrackerClient* client);
+  ~PageLoadTracker() override;
+
+ private:
+  struct LoadStatus {
+    // Set to true on receiving a notification from the renderer that the load
+    // finished. See WebContentsObserver::DidFinishLoad.
+    bool page_loaded = false;
+
+    // Set to true on receiving a notification from the renderer that the first
+    // paint after a navigation was performed.
+    // See WebContentsObserver::DidFirstPaintAfterLoad.
+    bool did_first_paint = false;
+
+    bool Loaded() const;
+  };
+
+  typedef base::SmallMap<std::map<content::RenderWidgetHost*, LoadStatus>>
+      RenderWidgetLoadStatusMap;
+
+  // content::WebContentsObserver implementation.
+  void DidStartProvisionalLoadForFrame(
+      content::RenderFrameHost* render_frame_host,
+      const GURL& validated_url,
+      bool is_error_page,
+      bool is_iframe_srcdoc) override;
+  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
+                     const GURL& validated_url) override;
+  void DidFailLoad(content::RenderFrameHost* render_frame_host,
+                   const GURL& validated_url,
+                   int error_code,
+                   const base::string16& error_description,
+                   bool was_ignored_by_handler) override;
+  void DidFirstPaintAfterLoad(
+      content::RenderWidgetHost* render_widget_host) override;
+
+  RenderWidgetLoadStatusMap render_widget_load_status_;
+
+  PageLoadTrackerClient* client_;
+
+  DISALLOW_COPY_AND_ASSIGN(PageLoadTracker);
+};
+
+}  // namespace engine
+}  // namespace blimp
+
+#endif  // BLIMP_ENGINE_SESSION_PAGE_LOAD_TRACKER_H_