Revert of Break page load metrics test dependency on IPC. (patchset #2...

Revert of Break page load metrics test dependency on IPC. (patchset #2 id:20001 of https://codereview.chromium.org/2847513002/ )

Reason for revert:
PageLoadMetricsBrowserTest.DocumentWriteReloada is flaky

https://luci-milo.appspot.com/buildbot/chromium.memory/Linux%20MSan%20Tests/387

Original issue's description:
> Break page load metrics test dependency on IPC.
>
> This change breaks direct dependencies on IPC for page load metrics
> tests, in order to ease the transition to mojo.
>
> Previously, unit tests exercised the IPC dispatch path. This
> achieved slightly increased coverage but coupled unit tests to
> IPC. We now dispatch simulated timing events directly to callbacks,
> bypassing the IPC dispatch.
>
> Additionally, we break the browsertest dependency on IPC and add
> a MetricsWebContentsObserver::TestingObserver, which can observe
> state changes at the observer level, instead of watching for IPC
> messages. This both simplifies the logic and more directly verifies
> expected behavior at the appropriate level.
>
> BUG=715744
> TBR=csharrison
>
> Review-Url: https://codereview.chromium.org/2847513002
> Cr-Commit-Position: refs/heads/master@{#467687}
> Committed: https://chromium.googlesource.com/chromium/src/+/9567f9fa3fcfcaa50fc7b6a6adf66106a2eb6be5

TBR=lpy@chromium.org,bmcquade@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=715744

Review-Url: https://codereview.chromium.org/2847803002
Cr-Commit-Position: refs/heads/master@{#467691}

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

@@ -64,6 +64,7 @@ UserInitiatedInfo CreateUserInitiatedInfo(
 
 }  // namespace
 
+// static
 MetricsWebContentsObserver::MetricsWebContentsObserver(
     content::WebContents* web_contents,
     std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface)
@@ -74,7 +75,6 @@ MetricsWebContentsObserver::MetricsWebContentsObserver(
   RegisterInputEventObserver(web_contents->GetRenderViewHost());
 }
 
-// static
 MetricsWebContentsObserver* MetricsWebContentsObserver::CreateForWebContents(
     content::WebContents* web_contents,
     std::unique_ptr<PageLoadMetricsEmbedderInterface> embedder_interface) {
@@ -92,9 +92,6 @@ MetricsWebContentsObserver* MetricsWebContentsObserver::CreateForWebContents(
 MetricsWebContentsObserver::~MetricsWebContentsObserver() {
   // TODO(csharrison): Use a more user-initiated signal for CLOSE.
   NotifyPageEndAllLoads(END_CLOSE, UserInitiatedInfo::NotUserInitiated());
-
-  for (auto& observer : testing_observers_)
-    observer.OnGoingAway();
 }
 
 void MetricsWebContentsObserver::RegisterInputEventObserver(
@@ -600,9 +597,6 @@ void MetricsWebContentsObserver::OnTimingUpdated(
   }
 
   committed_load_->UpdateTiming(timing, metadata);
-
-  for (auto& observer : testing_observers_)
-    observer.OnTimingUpdated(timing, metadata);
 }
 
 bool MetricsWebContentsObserver::ShouldTrackNavigation(
@@ -615,32 +609,4 @@ bool MetricsWebContentsObserver::ShouldTrackNavigation(
                                  navigation_handle).ShouldTrack();
 }
 
-void MetricsWebContentsObserver::AddTestingObserver(TestingObserver* observer) {
-  if (!testing_observers_.HasObserver(observer))
-    testing_observers_.AddObserver(observer);
-}
-
-void MetricsWebContentsObserver::RemoveTestingObserver(
-    TestingObserver* observer) {
-  testing_observers_.RemoveObserver(observer);
-}
-
-MetricsWebContentsObserver::TestingObserver::TestingObserver(
-    content::WebContents* web_contents)
-    : observer_(page_load_metrics::MetricsWebContentsObserver::FromWebContents(
-          web_contents)) {
-  observer_->AddTestingObserver(this);
-}
-
-MetricsWebContentsObserver::TestingObserver::~TestingObserver() {
-  if (observer_) {
-    observer_->RemoveTestingObserver(this);
-    observer_ = nullptr;
-  }
-}
-
-void MetricsWebContentsObserver::TestingObserver::OnGoingAway() {
-  observer_ = nullptr;
-}
-
 }  // namespace page_load_metrics

chrome/browser/page_load_metrics/metrics_web_contents_observer.h

@@ -10,7 +10,6 @@
 #include <vector>
 
 #include "base/macros.h"
-#include "base/observer_list.h"
 #include "base/time/time.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_observer.h"
 #include "chrome/common/page_load_metrics/page_load_timing.h"
@@ -44,27 +43,6 @@ class MetricsWebContentsObserver
       public content::WebContentsUserData<MetricsWebContentsObserver>,
       public content::RenderWidgetHost::InputEventObserver {
  public:
-  // TestingObserver allows tests to observe MetricsWebContentsObserver state
-  // changes. Tests may use TestingObserver to wait until certain state changes,
-  // such as the arrivial of PageLoadTiming messages from the render process,
-  // have been observed.
-  class TestingObserver {
-   public:
-    explicit TestingObserver(content::WebContents* web_contents);
-    virtual ~TestingObserver();
-
-    void OnGoingAway();
-
-    // Invoked when a new PageLoadTiming update has been received and processed.
-    virtual void OnTimingUpdated(const PageLoadTiming& timing,
-                                 const PageLoadMetadata& metadata) {}
-
-   private:
-    page_load_metrics::MetricsWebContentsObserver* observer_;
-
-    DISALLOW_COPY_AND_ASSIGN(TestingObserver);
-  };
-
   // Note that the returned metrics is owned by the web contents.
   static MetricsWebContentsObserver* CreateForWebContents(
       content::WebContents* web_contents,
@@ -131,15 +109,6 @@ class MetricsWebContentsObserver
   // This getter function is required for testing.
   const PageLoadExtraInfo GetPageLoadExtraInfoForCommittedLoad();
 
-  // Register / unregister TestingObservers. Should only be called from tests.
-  void AddTestingObserver(TestingObserver* observer);
-  void RemoveTestingObserver(TestingObserver* observer);
-
-  // public only for testing
-  void OnTimingUpdated(content::RenderFrameHost* render_frame_host,
-                       const PageLoadTiming& timing,
-                       const PageLoadMetadata& metadata);
-
  private:
   friend class content::WebContentsUserData<MetricsWebContentsObserver>;
 
@@ -180,6 +149,10 @@ class MetricsWebContentsObserver
       content::NavigationHandle* new_navigation,
       UserInitiatedInfo user_initiated_info);
 
+  void OnTimingUpdated(content::RenderFrameHost*,
+                       const PageLoadTiming& timing,
+                       const PageLoadMetadata& metadata);
+
   bool ShouldTrackNavigation(
       content::NavigationHandle* navigation_handle) const;
 
@@ -209,8 +182,6 @@ class MetricsWebContentsObserver
   // Has the MWCO observed at least one navigation?
   bool has_navigated_;
 
-  base::ObserverList<TestingObserver> testing_observers_;
-
   DISALLOW_COPY_AND_ASSIGN(MetricsWebContentsObserver);
 };
 

chrome/browser/page_load_metrics/metrics_web_contents_observer_unittest.cc

@@ -167,7 +167,10 @@ class MetricsWebContentsObserverTest : public ChromeRenderViewHostTestHarness {
 
   void SimulateTimingUpdate(const PageLoadTiming& timing,
                             content::RenderFrameHost* render_frame_host) {
-    observer_->OnTimingUpdated(render_frame_host, timing, PageLoadMetadata());
+    ASSERT_TRUE(observer_->OnMessageReceived(
+        PageLoadMetricsMsg_TimingUpdated(observer_->routing_id(), timing,
+                                         PageLoadMetadata()),
+        render_frame_host));
   }
 
   void AttachObserver() {

chrome/browser/page_load_metrics/observers/page_load_metrics_observer_test_harness.cc

@@ -144,7 +144,9 @@ void PageLoadMetricsObserverTestHarness::SimulateTimingUpdate(
 void PageLoadMetricsObserverTestHarness::SimulateTimingAndMetadataUpdate(
     const PageLoadTiming& timing,
     const PageLoadMetadata& metadata) {
-  observer_->OnTimingUpdated(web_contents()->GetMainFrame(), timing, metadata);
+  observer_->OnMessageReceived(PageLoadMetricsMsg_TimingUpdated(
+                                   observer_->routing_id(), timing, metadata),
+                               web_contents()->GetMainFrame());
 }
 
 void PageLoadMetricsObserverTestHarness::SimulateStartedResource(