Clean up logic to determine if a navigation is from GWS.

chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h b/chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h
index 0465ede23619906d8eefeaae1f945b34c6a43681..429bd90fd845e0ebc05f3e82dcc3453d9a539848 100644
--- a/chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/observers/from_gws_page_load_metrics_observer.h
@@ -7,24 +7,90 @@
 
 #include "base/macros.h"
 #include "components/page_load_metrics/browser/page_load_metrics_observer.h"
+#include "url/gurl.h"
+
+namespace internal {
+// Exposed for tests.
+extern const char kHistogramFromGWSFirstTextPaint[];
+}  // namespace internal
+
+// FromGWSPageLoadMetricsLogger is a peer class to
+// FromGWSPageLoadMetricsObserver. FromGWSPageLoadMetricsLogger is responsible
+// for tracking state needed to decide if metrics should be logged, and to log
+// metrics in cases where metrics should be logged. FromGWSPageLoadMetricsLogger
+// exists to decouple the logging policy implementation from other Chromium
+// classes such as NavigationHandle and related infrastructure, in order to make
+// the code more unit testable.
+class FromGWSPageLoadMetricsLogger {
+ public:
+  FromGWSPageLoadMetricsLogger() {}
+
+  void set_previously_committed_url(const GURL& url) {
+    previously_committed_url_ = url;
+  }
+
+  void set_navigation_initiated_via_link(bool navigation_initiated_via_link) {
+    navigation_initiated_via_link_ = navigation_initiated_via_link;
+  }
+
+  // Invoked when metrics for the given page are complete.
+  void OnComplete(const page_load_metrics::PageLoadTiming& timing,
+                  const page_load_metrics::PageLoadExtraInfo& extra_info);
+
+  // The methods below are public only for testing.
+  static bool IsGoogleSearchHostname(base::StringPiece host);
+  static bool IsGoogleSearchResultUrl(const GURL& url);
+  static bool IsGoogleRedirectorUrl(const GURL& url);
+  static bool IsGoogleSearchRedirectorUrl(const GURL& url);
+
+  // Whether the given query string contains the given component. The query
+  // parameter should contain the query string of a URL (the portion following
+  // the question mark, excluding the question mark). The component must fully
+  // match a component in the query string. For example, 'foo=bar' would match
+  // the query string 'a=b&foo=bar&c=d' but would not match 'a=b&zzzfoo=bar&c=d'
+  // since, though foo=bar appears in the query string, the key specified in the
+  // component 'foo' does not match the full key in the query string
+  // 'zzzfoo'. For QueryContainsComponent, the component should of the form
+  // 'key=value'. For QueryContainsComponentPrefix, the component should be of
+  // the form 'key=' (where the value is not specified).
+  static bool QueryContainsComponent(const base::StringPiece query,
+                                     const base::StringPiece component);
+  static bool QueryContainsComponentPrefix(const base::StringPiece query,
+                                           const base::StringPiece component);
+
+  // Whether metrics should be logged based on state provided via setters and
+  // the given committed_url.
+  bool ShouldLogMetrics(const GURL& committed_url) const;
+
+ private:
+  GURL previously_committed_url_;
+  bool navigation_initiated_via_link_ = false;
+
+  // Common helper for QueryContainsComponent and QueryContainsComponentPrefix.
+  static bool QueryContainsComponentHelper(const base::StringPiece query,
+                                           const base::StringPiece component,
+                                           bool component_is_prefix);
+
+  void LogMetrics(const page_load_metrics::PageLoadTiming& timing,
+                  const page_load_metrics::PageLoadExtraInfo& extra_info);
+
+  DISALLOW_COPY_AND_ASSIGN(FromGWSPageLoadMetricsLogger);
+};
 
 class FromGWSPageLoadMetricsObserver
     : public page_load_metrics::PageLoadMetricsObserver {
  public:
   FromGWSPageLoadMetricsObserver();
   // page_load_metrics::PageLoadMetricsObserver implementation:
+  void OnStart(content::NavigationHandle* navigation_handle,
+               const GURL& currently_committed_url) override;
   void OnCommit(content::NavigationHandle* navigation_handle) override;
   void OnComplete(
       const page_load_metrics::PageLoadTiming& timing,
       const page_load_metrics::PageLoadExtraInfo& extra_info) override;
 
- protected:
-  // Called in tests.
-  void SetCommittedURLAndReferrer(const GURL& url,
-                                  const content::Referrer& referrer);
-
  private:
-  bool navigation_from_gws_;
+  FromGWSPageLoadMetricsLogger logger_;
 
   DISALLOW_COPY_AND_ASSIGN(FromGWSPageLoadMetricsObserver);
 };