Track frame context URL using first script heuristic

BUG=635596

Review-Url: https://codereview.chromium.org/2296923004
Cr-Commit-Position: refs/heads/master@{#418931}

third_party/WebKit/Source/core/BUILD.gn

@@ -1126,6 +1126,7 @@ source_set("unit_tests") {
     "html/track/vtt/BufferedLineReaderTest.cpp",
     "html/track/vtt/VTTScannerTest.cpp",
     "input/EventHandlerTest.cpp",
+    "inspector/InspectorWebPerfAgentTest.cpp",
     "inspector/ProtocolParserTest.cpp",
     "layout/ImageQualityControllerTest.cpp",
     "layout/InlineTextBoxTest.cpp",

third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.cpp

@@ -4,22 +4,39 @@
 
 #include "core/inspector/InspectorWebPerfAgent.h"
 
+#include "core/dom/Document.h"
+#include "core/dom/ExecutionContext.h"
 #include "core/frame/LocalFrame.h"
+#include "core/frame/Location.h"
 #include "core/inspector/InspectedFrames.h"
+#include "public/platform/Platform.h"
 
 namespace blink {
 
 InspectorWebPerfAgent::InspectorWebPerfAgent(InspectedFrames* inspectedFrames)
     : m_inspectedFrames(inspectedFrames)
 {
+    Platform::current()->currentThread()->addTaskTimeObserver(this);
+    Platform::current()->currentThread()->addTaskObserver(this);
 }
 
 InspectorWebPerfAgent::~InspectorWebPerfAgent()
 {
+    Platform::current()->currentThread()->removeTaskTimeObserver(this);
+    Platform::current()->currentThread()->removeTaskObserver(this);
 }
 
 void InspectorWebPerfAgent::willExecuteScript(ExecutionContext* context)
 {
+    // Heuristic for minimal frame context attribution: note the Location URL
+    // for each script execution. When a long task is encountered,
+    // if there is only one Location URL involved, then report it.
+    // Otherwise don't report Location URL.
+    // NOTE: This heuristic is imperfect and will be improved in V2 API.
+    // In V2, timing of script execution along with style & layout updates will be
+    // accounted for detailed and more accurate attribution.
+    if (context->isDocument())
+        m_frameContextLocations.add(toDocument(context)->location());
 }
 
 void InspectorWebPerfAgent::didExecuteScript()
@@ -28,6 +45,9 @@ void InspectorWebPerfAgent::didExecuteScript()
 
 void InspectorWebPerfAgent::willProcessTask()
 {
+    // Reset m_frameContextLocations. We don't clear this in didProcessTask
+    // as it is needed in ReportTaskTime which occurs after didProcessTask.
+    m_frameContextLocations.clear();
 }
 
 void InspectorWebPerfAgent::didProcessTask()
@@ -41,6 +61,7 @@ void InspectorWebPerfAgent::ReportTaskTime(double startTime, double endTime)
 DEFINE_TRACE(InspectorWebPerfAgent)
 {
     visitor->trace(m_inspectedFrames);
+    visitor->trace(m_frameContextLocations);
 }
 
 } // namespace blink

third_party/WebKit/Source/core/inspector/InspectorWebPerfAgent.h

@@ -14,6 +14,7 @@ namespace blink {
 
 class ExecutionContext;
 class LocalFrame;
+class Location;
 class InspectedFrames;
 
 // Inspector Agent for Web Performance APIs
@@ -22,6 +23,7 @@ class CORE_EXPORT InspectorWebPerfAgent final
     , public WebThread::TaskObserver
     , public scheduler::TaskTimeObserver {
     WTF_MAKE_NONCOPYABLE(InspectorWebPerfAgent);
+    friend class InspectorWebPerfAgentTest;
 public:
     explicit InspectorWebPerfAgent(InspectedFrames*);
     ~InspectorWebPerfAgent();
@@ -39,6 +41,7 @@ public:
 
 private:
     Member<InspectedFrames> m_inspectedFrames;
+    HeapHashSet<Member<Location>> m_frameContextLocations;
 };
 
 } // namespace blink

third_party/WebKit/Source/core/inspector/InspectorWebPerfAgentTest.cpp

+// 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 "core/inspector/InspectorWebPerfAgent.h"
+
+#include "core/frame/Location.h"
+#include "core/inspector/InspectedFrames.h"
+#include "core/testing/DummyPageHolder.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "wtf/PtrUtil.h"
+
+#include <memory>
+
+namespace blink {
+
+class InspectorWebPerfAgentTest : public ::testing::Test {
+protected:
+    void SetUp() override;
+    LocalFrame* frame() const { return m_pageHolder->document().frame(); }
+    ExecutionContext* executionContext() const { return &m_pageHolder->document(); }
+    ExecutionContext* anotherExecutionContext() const { return &m_anotherPageHolder->document(); }
+
+    String frameContextURL();
+    int numUniqueFrameContextsSeen();
+
+    Persistent<InspectorWebPerfAgent> m_agent;
+    std::unique_ptr<DummyPageHolder> m_pageHolder;
+    std::unique_ptr<DummyPageHolder> m_anotherPageHolder;
+};
+
+void InspectorWebPerfAgentTest::SetUp()
+{
+    m_pageHolder = DummyPageHolder::create(IntSize(800, 600));
+    m_pageHolder->document().setURL(KURL(KURL(), "https://example.com/foo"));
+    m_agent = new InspectorWebPerfAgent(InspectedFrames::create(frame()));
+
+    // Create another dummy page holder and pretend this is the iframe.
+    m_anotherPageHolder = DummyPageHolder::create(IntSize(400, 300));
+    m_anotherPageHolder->document().setURL(KURL(KURL(), "https://iframed.com/bar"));
+}
+
+String InspectorWebPerfAgentTest::frameContextURL()
+{
+    // This is reported only if there is a single frameContext URL.
+    if (m_agent->m_frameContextLocations.size() != 1)
+        return "";
+    for (Member<Location> location : m_agent->m_frameContextLocations) {
+        return String(location->protocol()) + "//"
+            + location->hostname() + location->pathname();
+    }
+    return "";
+}
+
+int InspectorWebPerfAgentTest::numUniqueFrameContextsSeen()
+{
+    return m_agent->m_frameContextLocations.size();
+}
+
+TEST_F(InspectorWebPerfAgentTest, SingleScriptInTask)
+{
+    m_agent->willProcessTask();
+    EXPECT_EQ(0, numUniqueFrameContextsSeen());
+    m_agent->willExecuteScript(executionContext());
+    EXPECT_EQ(1, numUniqueFrameContextsSeen());
+    m_agent->didExecuteScript();
+    m_agent->didProcessTask();
+    m_agent->ReportTaskTime(3719349.445172, 3719349.5561923); // Long task
+    EXPECT_EQ(1, numUniqueFrameContextsSeen());
+    EXPECT_EQ("https://example.com/foo", frameContextURL());
+}
+
+TEST_F(InspectorWebPerfAgentTest, MultipleScriptsInTask_SingleContext)
+{
+    m_agent->willProcessTask();
+    EXPECT_EQ(0, numUniqueFrameContextsSeen());
+    m_agent->willExecuteScript(executionContext());
+    EXPECT_EQ(1, numUniqueFrameContextsSeen());
+    m_agent->didExecuteScript();
+    EXPECT_EQ("https://example.com/foo", frameContextURL());
+
+    m_agent->willExecuteScript(executionContext());
+    EXPECT_EQ(1, numUniqueFrameContextsSeen());
+    m_agent->didExecuteScript();
+    m_agent->didProcessTask();
+    m_agent->ReportTaskTime(3719349.445172, 3719349.5561923); // Long task
+    EXPECT_EQ(1, numUniqueFrameContextsSeen());
+    EXPECT_EQ("https://example.com/foo", frameContextURL());
+}
+
+TEST_F(InspectorWebPerfAgentTest, MultipleScriptsInTask_MultipleContexts)
+{
+    m_agent->willProcessTask();
+    EXPECT_EQ(0, numUniqueFrameContextsSeen());
+    m_agent->willExecuteScript(executionContext());
+    EXPECT_EQ(1, numUniqueFrameContextsSeen());
+    m_agent->didExecuteScript();
+    EXPECT_EQ("https://example.com/foo", frameContextURL());
+
+    m_agent->willExecuteScript(anotherExecutionContext());
+    EXPECT_EQ(2, numUniqueFrameContextsSeen());
+    m_agent->didExecuteScript();
+    m_agent->didProcessTask();
+    m_agent->ReportTaskTime(3719349.445172, 3719349.5561923); // Long task
+    EXPECT_EQ(2, numUniqueFrameContextsSeen());
+    EXPECT_EQ("", frameContextURL());
+}
+
+TEST_F(InspectorWebPerfAgentTest, NoScriptInLongTask)
+{
+    m_agent->willProcessTask();
+    m_agent->willExecuteScript(executionContext());
+    m_agent->didExecuteScript();
+    m_agent->didProcessTask();
+    m_agent->ReportTaskTime(3719349.445172, 3719349.445182);
+    m_agent->willProcessTask();
+    m_agent->didProcessTask();
+    m_agent->ReportTaskTime(3719349.445172, 3719349.5561923); // Long task
+    // Without presence of Script, FrameContext URL is not available
+    EXPECT_EQ(0, numUniqueFrameContextsSeen());
+}
+
+} // namespace blink