Update OnCommit to return ObservePolicy.

chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.cc

 // 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.
 
 #include "chrome/browser/page_load_metrics/observers/data_reduction_proxy_metrics_observer.h"
 
 #include <string>
 
 #include "base/optional.h"
 #include "base/time/time.h"
@@ skipping 73 matching lines @@
 const char kHistogramParseDurationSuffix[] = "ParseTiming.ParseDuration";
 
 }  // namespace internal
 
 DataReductionProxyMetricsObserver::DataReductionProxyMetricsObserver()
     : browser_context_(nullptr) {}
 
 DataReductionProxyMetricsObserver::~DataReductionProxyMetricsObserver() {}
 
 // Check if the NavigationData indicates anything about the DataReductionProxy.
-void DataReductionProxyMetricsObserver::OnCommit(
+page_load_metrics::PageLoadMetricsObserver::ObservePolicy
+DataReductionProxyMetricsObserver::OnCommit(
     content::NavigationHandle* navigation_handle) {
   // This BrowserContext is valid for the lifetime of
   // DataReductionProxyMetricsObserver. BrowserContext is always valid and
   // non-nullptr in NavigationControllerImpl, which is a member of WebContents.
   // A raw pointer to BrowserContext taken at this point will be valid until
   // after WebContent's destructor. The latest that PageLoadTracker's destructor
   // will be called is in MetricsWebContentsObserver's destrcutor, which is
   // called in WebContents destructor.
   browser_context_ = navigation_handle->GetWebContents()->GetBrowserContext();
   // As documented in content/public/browser/navigation_handle.h, this
   // NavigationData is a clone of the NavigationData instance returned from
   // ResourceDispatcherHostDelegate::GetNavigationData during commit.
   // Because ChromeResourceDispatcherHostDelegate always returns a
   // ChromeNavigationData, it is safe to static_cast here.
   ChromeNavigationData* chrome_navigation_data =
       static_cast<ChromeNavigationData*>(
           navigation_handle->GetNavigationData());
   if (!chrome_navigation_data)
-    return;
+    return STOP_OBSERVING;
   data_reduction_proxy::DataReductionProxyData* data =
       chrome_navigation_data->GetDataReductionProxyData();
   if (!data)
-    return;
+    return STOP_OBSERVING;
   data_ = data->DeepCopy();
   // DataReductionProxy page loads should only occur on HTTP navigations.
   DCHECK(!data_->used_data_reduction_proxy() ||
          !navigation_handle->GetURL().SchemeIsCryptographic());
+  return CONTINUE_OBSERVING;
 }
 
 void DataReductionProxyMetricsObserver::OnComplete(
     const page_load_metrics::PageLoadTiming& timing,
     const page_load_metrics::PageLoadExtraInfo& info) {
   // TODO(ryansturm): Move to OnFirstBackgroundEvent to handle some fast
   // shutdown cases. crbug.com/618072
   if (!browser_context_)
     return;
   if (!data_ || !data_->used_data_reduction_proxy())
@@ skipping 123 matching lines @@
 
 DataReductionProxyPingbackClient*
 DataReductionProxyMetricsObserver::GetPingbackClient() const {
   return DataReductionProxyChromeSettingsFactory::GetForBrowserContext(
              browser_context_)
       ->data_reduction_proxy_service()
       ->pingback_client();
 }
 
 }  // namespace data_reduction_proxy