[profiler] Reintroduce context filtering in blink

Provide a non-null |v8::Context| param to filter profiles by originating
context, now that context filtering has been reintroduced in blink.
Modify existing WPTs to be compliant with this, as well as use a more
realistic test for filtering.

Bug: 956688
Change-Id: I60c23fdac29af9f452d21f57496fd2f8fc20826e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2852074
Reviewed-by: Nicolás Peña Moreno <npm@chromium.org>
Commit-Queue: Andrew Comminos <acomminos@fb.com>
Cr-Commit-Position: refs/heads/master@{#878111}

third_party/blink/renderer/core/timing/profiler_group.cc

@@ -182,7 +182,7 @@ Profiler* ProfilerGroup::CreateProfiler(ScriptState* script_state,
       v8::kLeafNodeLineNumbers,
       init_options.hasMaxBufferSize() ? init_options.maxBufferSize()
                                       : v8::CpuProfilingOptions::kNoSampleLimit,
-      static_cast<int>(sample_interval_us), v8::MaybeLocal<v8::Context>());
+      static_cast<int>(sample_interval_us), script_state->GetContext());
 
   v8::CpuProfilingStatus status = cpu_profiler_->StartProfiling(
       V8String(isolate_, profiler_id), options,

third_party/blink/web_tests/wpt_internal/js-self-profiling/iframe-context-filtration.https.html

@@ -10,10 +10,6 @@
   <iframe src="resources/child-frame.html"></iframe>
 
   <script>
-    function parentCollectSample(profiler) {
-      ProfileUtils.forceSample(profiler);
-    }
-
     promise_test(_ => new Promise(res => window.addEventListener('load', res)),
                  'wait for load event');
 
@@ -23,54 +19,17 @@
       });
 
       const iframe = frames[0];
-      function parentWrapper() {
-        iframe.childCollectSample(profiler);
-      }
-      parentWrapper();
-
-      const trace = await profiler.stop();
-
-      assert_true(ProfileUtils.containsFrame(trace, { name: 'parentWrapper' }),
-                  'function from own (parent) context included in trace');
-
-      assert_true(ProfileUtils.containsFrame(trace, { name: 'childCollectSample' }),
-                   'function from child context included in trace');
-
-      assert_true(ProfileUtils.containsFrame(trace, { name: 'parentCollectSample' }),
-                  'sampling wrapper function from own (parent) context included in trace');
-
-      const childUrl = iframe.location.href;
-      assert_true(ProfileUtils.containsResource(trace, childUrl),
-                  'child resources are included');
-    }, 'functions from child frame are included in profile created by parent frame');
-
-    promise_test(async t => {
-      const iframe = frames[0];
-      const profiler = await iframe.childCreateProfiler({
-        sampleInterval: 10,
-      });
-
-      (function parentWrapper() {
-        iframe.childCollectSample(profiler);
-      })();
+      await ProfileUtils.forceSampleFrame(iframe);
 
       const trace = await profiler.stop();
 
-      assert_true(ProfileUtils.containsFrame(trace, { name: 'parentWrapper' }),
-                  'function from parent context included in trace');
-
-      assert_true(ProfileUtils.containsFrame(trace, { name: 'childCollectSample' }),
-                  'function from own (child) context included in trace');
-
-      assert_true(ProfileUtils.containsResource(trace,
-        window.location.href,
-      ), 'parent resource is included');
-
-      assert_true(ProfileUtils.containsResource(trace,
-        iframe.location.href,
-      ), 'child resource is included');
+      assert_false(ProfileUtils.containsFrame(trace, { name: 'sampleFromMessage' }),
+                   'function from child context not included in trace');
 
-    }, 'functions from parent context are included in profile created by child frame');
+      const childUrl = iframe.src;
+      assert_false(ProfileUtils.containsResource(trace, childUrl),
+                  'child resources are not included');
+    }, 'functions from child frame are not included in profile created by parent frame');
   </script>
 </body>
 </html>

third_party/blink/web_tests/wpt_internal/js-self-profiling/max-buffer-size.https.html

@@ -24,13 +24,18 @@
     }, 'max buffer size is not exceeded');
 
     promise_test(async t => {
-    const profiler = await performance.profile({
-      sampleInterval: 10,
-      maxBufferSize: 1,
-    });
+      const profiler = await performance.profile({
+        sampleInterval: 10,
+        maxBufferSize: 1,
+      });
+
+      const watcher = new EventWatcher(t, profiler, ['samplebufferfull']);
+
+      for (let i = 0; i < 10; i++) {
+        ProfileUtils.forceSample();
+      }
 
-    const watcher = new EventWatcher(t, profiler, ['samplebufferfull']);
-    return watcher.wait_for('samplebufferfull');
+      return watcher.wait_for('samplebufferfull');
     }, 'executed samplebufferfull function');
   </script>
 </body>

third_party/blink/web_tests/wpt_internal/js-self-profiling/resources/child-frame.html

@@ -3,14 +3,6 @@
 <head>
 </head>
 <body>
-  <script>
-    function childCreateProfiler(options) {
-      return performance.profile(options);
-    }
-
-    function childCollectSample(profiler) {
-      top.parentCollectSample(profiler);
-    }
-  </script>
+  <script src="profile-utils.js"></script>
 </body>
 </html>

third_party/blink/web_tests/wpt_internal/js-self-profiling/resources/profile-utils.js

@@ -83,6 +83,23 @@
            (expected.column === undefined || expected.column === actual.column);
   }
 
+  function forceSampleFrame(frame) {
+    const channel = new MessageChannel();
+    const replyPromise = new Promise(res => {
+      channel.port1.onmessage = res;
+    });
+    frame.postMessage('', '*', [channel.port2]);
+    return replyPromise;
+  }
+
+  window.addEventListener('message', message => {
+    // Force sample in response to messages received.
+    (function sampleFromMessage() {
+      ProfileUtils.forceSample();
+      message.ports[0].postMessage('');
+    })();
+  });
+
   global.ProfileUtils = {
     // Capturing
     profileFunction,
@@ -93,6 +110,9 @@
     containsSubstack,
     containsResource,
 
+    // Cross-frame sampling
+    forceSampleFrame,
+
     // Assertions
     testFunction,
   };