Retire ScopedObserver in /components/metrics.

ScopedObserver is being deprecated in favor of two new classes:
- base::ScopedObservation for observers that only ever observe
  a single source.
- base::ScopedMultiSourceObservation for observers that do or may
  observe more than a single source.

This CL was uploaded by git cl split.

R=bcwhite@chromium.org

Bug: 1145565
Change-Id: I68423d748501ffba5239606311b518844e1c51a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532955
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826489}

components/metrics/content/content_stability_metrics_provider.cc

@@ -28,12 +28,7 @@ namespace metrics {
 ContentStabilityMetricsProvider::ContentStabilityMetricsProvider(
     PrefService* local_state,
     std::unique_ptr<ExtensionsHelper> extensions_helper)
-    :
-#if defined(OS_ANDROID)
-      scoped_observer_(this),
-#endif  // defined(OS_ANDROID)
-      helper_(local_state),
-      extensions_helper_(std::move(extensions_helper)) {
+    : helper_(local_state), extensions_helper_(std::move(extensions_helper)) {
   BrowserChildProcessObserver::Add(this);
 
   registrar_.Add(this, content::NOTIFICATION_LOAD_START,
@@ -48,7 +43,7 @@ ContentStabilityMetricsProvider::ContentStabilityMetricsProvider(
 #if defined(OS_ANDROID)
   auto* crash_manager = crash_reporter::CrashMetricsReporter::GetInstance();
   DCHECK(crash_manager);
-  scoped_observer_.Add(crash_manager);
+  scoped_observation_.Observe(crash_manager);
 #endif  // defined(OS_ANDROID)
 }
 

components/metrics/content/content_stability_metrics_provider.h

@@ -8,7 +8,7 @@
 #include <memory>
 
 #include "base/gtest_prod_util.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "build/build_config.h"
 #include "components/metrics/metrics_provider.h"
 #include "components/metrics/stability_metrics_helper.h"
@@ -84,9 +84,9 @@ class ContentStabilityMetricsProvider
       const crash_reporter::CrashMetricsReporter::ReportedCrashTypeSet&
           reported_counts) override;
 
-  ScopedObserver<crash_reporter::CrashMetricsReporter,
-                 crash_reporter::CrashMetricsReporter::Observer>
-      scoped_observer_;
+  base::ScopedObservation<crash_reporter::CrashMetricsReporter,
+                          crash_reporter::CrashMetricsReporter::Observer>
+      scoped_observation_{this};
 #endif  // defined(OS_ANDROID)
 
   StabilityMetricsHelper helper_;

components/metrics/content/subprocess_metrics_provider.cc

@@ -162,8 +162,8 @@ void SubprocessMetricsProvider::OnRenderProcessHostCreated(
     content::RenderProcessHost* host) {
   // Sometimes, the same host will cause multiple notifications in tests so
   // could possibly do the same in a release build.
-  if (!scoped_observer_.IsObserving(host))
-    scoped_observer_.Add(host);
+  if (!scoped_observations_.IsObservingSource(host))
+    scoped_observations_.AddObservation(host);
 }
 
 void SubprocessMetricsProvider::RenderProcessReady(
@@ -198,7 +198,7 @@ void SubprocessMetricsProvider::RenderProcessHostDestroyed(
   // destruction of the host. If both get called, no harm is done.
 
   DeregisterSubprocessAllocator(host->GetID());
-  scoped_observer_.Remove(host);
+  scoped_observations_.RemoveObservation(host);
 }
 
 // static

components/metrics/content/subprocess_metrics_provider.h

@@ -12,7 +12,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/metrics/statistics_recorder.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_multi_source_observation.h"
 #include "base/threading/thread_checker.h"
 #include "components/metrics/metrics_provider.h"
 #include "content/public/browser/browser_child_process_observer.h"
@@ -109,8 +109,9 @@ class SubprocessMetricsProvider
   AllocatorByIdMap allocators_by_id_;
 
   // Track all observed render processes to un-observe them on exit.
-  ScopedObserver<content::RenderProcessHost, content::RenderProcessHostObserver>
-      scoped_observer_{this};
+  base::ScopedMultiSourceObservation<content::RenderProcessHost,
+                                     content::RenderProcessHostObserver>
+      scoped_observations_{this};
 
   base::WeakPtrFactory<SubprocessMetricsProvider> weak_ptr_factory_{this};
 

components/metrics/content/subprocess_metrics_provider_browsertest.cc

@@ -66,10 +66,10 @@ class SubprocessMetricsProviderBrowserTest
     return provider_->allocators_by_id_;
   }
 
-  ScopedObserver<content::RenderProcessHost,
-                 content::RenderProcessHostObserver>&
-  get_scoped_observer() {
-    return provider_->scoped_observer_;
+  base::ScopedMultiSourceObservation<content::RenderProcessHost,
+                                     content::RenderProcessHostObserver>&
+  get_scoped_observations() {
+    return provider_->scoped_observations_;
   }
 
   base::PersistentHistogramAllocator* GetMainFrameAllocator() {
@@ -114,7 +114,7 @@ IN_PROC_BROWSER_TEST_F(SubprocessMetricsProviderBrowserTest,
                        RegisterExistingNotReadyRenderProcesses) {
   ASSERT_TRUE(GetRenderProcessHostCount() > 0);
   CreateSubprocessMetricsProvider();
-  EXPECT_EQ(get_scoped_observer().GetSourcesCount(),
+  EXPECT_EQ(get_scoped_observations().GetSourcesCount(),
             GetRenderProcessHostCount());
   EXPECT_EQ(get_allocators_by_id().size(), 0u);
 
@@ -123,7 +123,7 @@ IN_PROC_BROWSER_TEST_F(SubprocessMetricsProviderBrowserTest,
 
   // Verify that the number of scoped observer matches the number of
   // RenderProcessHost and the main frame allocator exists.
-  EXPECT_EQ(get_scoped_observer().GetSourcesCount(),
+  EXPECT_EQ(get_scoped_observations().GetSourcesCount(),
             GetRenderProcessHostCount());
   auto* main_frame_allocator = GetMainFrameAllocator();
   EXPECT_TRUE(main_frame_allocator);
@@ -156,7 +156,8 @@ IN_PROC_BROWSER_TEST_F(SubprocessMetricsProviderBrowserTest,
       shell()->web_contents()->GetMainFrame()->GetProcess();
   SimulateRenderProcessHostDestroyed();
   // Verify the observer removed.
-  EXPECT_FALSE(get_scoped_observer().IsObserving(main_frame_process_host));
+  EXPECT_FALSE(
+      get_scoped_observations().IsObservingSource(main_frame_process_host));
 }
 
 IN_PROC_BROWSER_TEST_F(SubprocessMetricsProviderBrowserTest,
@@ -169,7 +170,7 @@ IN_PROC_BROWSER_TEST_F(SubprocessMetricsProviderBrowserTest,
 
   // Verify that the number of scoped observer matches the number of
   // RenderProcessHost and the main frame allocator exists.
-  EXPECT_EQ(get_scoped_observer().GetSourcesCount(),
+  EXPECT_EQ(get_scoped_observations().GetSourcesCount(),
             GetRenderProcessHostCount());
   auto* main_frame_allocator = GetMainFrameAllocator();
   EXPECT_TRUE(main_frame_allocator);
@@ -202,7 +203,8 @@ IN_PROC_BROWSER_TEST_F(SubprocessMetricsProviderBrowserTest,
       shell()->web_contents()->GetMainFrame()->GetProcess();
   SimulateRenderProcessHostDestroyed();
   // Verify the observer removed.
-  EXPECT_FALSE(get_scoped_observer().IsObserving(main_frame_process_host));
+  EXPECT_FALSE(
+      get_scoped_observations().IsObservingSource(main_frame_process_host));
 }
 
 }  // namespace metrics