Factor PageLoadTracker into its own header and impl files.

metrics_web_contents_observer.h/.cc have become quite complex.
This change factors the PageLoadTracker code into its own files,
in order to make each individual file more manageable.

Review-Url: https://codereview.chromium.org/2435233002
Cr-Commit-Position: refs/heads/master@{#427216}

chrome/browser/BUILD.gn

@@ -717,12 +717,15 @@ split_static_library("browser") {
     "page_load_metrics/observers/previews_page_load_metrics_observer.h",
     "page_load_metrics/observers/service_worker_page_load_metrics_observer.cc",
     "page_load_metrics/observers/service_worker_page_load_metrics_observer.h",
+    "page_load_metrics/page_load_metrics_embedder_interface.h",
     "page_load_metrics/page_load_metrics_initialize.cc",
     "page_load_metrics/page_load_metrics_initialize.h",
     "page_load_metrics/page_load_metrics_observer.cc",
     "page_load_metrics/page_load_metrics_observer.h",
     "page_load_metrics/page_load_metrics_util.cc",
     "page_load_metrics/page_load_metrics_util.h",
+    "page_load_metrics/page_load_tracker.cc",
+    "page_load_metrics/page_load_tracker.h",
     "password_manager/chrome_password_manager_client.cc",
     "password_manager/chrome_password_manager_client.h",
     "password_manager/password_manager_setting_migrator_service_factory.cc",

chrome/browser/page_load_metrics/browser_page_track_decider.cc

@@ -6,7 +6,7 @@
 
 #include <string>
 
-#include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/web_contents.h"
 #include "net/http/http_response_headers.h"

chrome/browser/page_load_metrics/metrics_web_contents_observer_unittest.cc

@@ -13,7 +13,9 @@
 #include "base/test/histogram_tester.h"
 #include "base/time/time.h"
 #include "chrome/browser/page_load_metrics/metrics_navigation_throttle.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/page_load_tracker.h"
 #include "chrome/common/page_load_metrics/page_load_metrics_messages.h"
 #include "chrome/test/base/chrome_render_view_host_test_harness.h"
 #include "content/public/browser/navigation_handle.h"

chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.cc

@@ -4,7 +4,6 @@
 
 #include "chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.h"
 
-#include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "content/public/browser/navigation_handle.h"

chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.cc

@@ -8,6 +8,7 @@
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h"
 #include "chrome/common/page_load_metrics/page_load_metrics_messages.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/web_contents.h"

chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.h

@@ -8,6 +8,7 @@
 #include "base/macros.h"
 #include "base/test/histogram_tester.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
+#include "chrome/browser/page_load_metrics/page_load_tracker.h"
 #include "chrome/test/base/chrome_render_view_host_test_harness.h"
 #include "content/public/test/web_contents_tester.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

@@ -11,6 +11,7 @@
 #include "chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/page_load_tracker.h"
 #include "chrome/browser/prerender/prerender_histograms.h"
 #include "chrome/browser/prerender/prerender_origin.h"
 #include "chrome/browser/profiles/profile.h"

chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h

+// 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 CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_EMBEDDER_INTERFACE_H_
+#define CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_EMBEDDER_INTERFACE_H_
+
+class GURL;
+
+namespace content {
+class WebContents;
+}  // namespace content
+
+namespace page_load_metrics {
+
+class PageLoadTracker;
+
+// This class serves as a functional interface to various chrome// features.
+// Impl version is defined in chrome/browser/page_load_metrics.
+class PageLoadMetricsEmbedderInterface {
+ public:
+  virtual ~PageLoadMetricsEmbedderInterface() {}
+  virtual bool IsPrerendering(content::WebContents* web_contents) = 0;
+  virtual bool IsNewTabPageUrl(const GURL& url) = 0;
+  virtual void RegisterObservers(PageLoadTracker* metrics) = 0;
+};
+
+}  // namespace page_load_metrics
+
+#endif  // CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_EMBEDDER_INTERFACE_H_

chrome/browser/page_load_metrics/page_load_metrics_initialize.cc

@@ -21,6 +21,8 @@
 #include "chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h"
+#include "chrome/browser/page_load_metrics/page_load_tracker.h"
 #include "chrome/browser/prerender/prerender_contents.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/search.h"