Remove some tracing methods from blink::Platform

Now we can directly use trace_event macros to implement EventTracer. Remove
unnecessary indirections. This is also a preparation to add
EstimateTraceMemoryOverhead() to blink's TracedValue.

BUG=561879, 570961

Review URL: https://codereview.chromium.org/1544123002

Cr-Commit-Position: refs/heads/master@{#370066}

15 files changed, 80 insertions, 355 deletions

diff --git a/components/html_viewer/blink_platform_impl.cc b/components/html_viewer/blink_platform_impl.cc
index c3d5d1a..714f16f 100644
--- a/components/html_viewer/blink_platform_impl.cc
+++ b/components/html_viewer/blink_platform_impl.cc
@@ -153,12 +153,6 @@ blink::WebScrollbarBehavior* BlinkPlatformImpl::scrollbarBehavior() {
   return &scrollbar_behavior_;
 }
 
-const unsigned char* BlinkPlatformImpl::getTraceCategoryEnabledFlag(
-    const char* category_name) {
-  static const unsigned char buf[] = "*";
-  return buf;
-}
-
 blink::WebGraphicsContext3D*
 BlinkPlatformImpl::createOffscreenGraphicsContext3D(
     const blink::WebGraphicsContext3D::Attributes& attributes,
diff --git a/components/html_viewer/blink_platform_impl.h b/components/html_viewer/blink_platform_impl.h
index df74298..0494d1c 100644
--- a/components/html_viewer/blink_platform_impl.h
+++ b/components/html_viewer/blink_platform_impl.h
@@ -77,8 +77,6 @@ class BlinkPlatformImpl : public blink::Platform {
   blink::WebWaitableEvent* waitMultipleEvents(
       const blink::WebVector<blink::WebWaitableEvent*>& events) override;
   blink::WebScrollbarBehavior* scrollbarBehavior() override;
-  const unsigned char* getTraceCategoryEnabledFlag(
-      const char* category_name) override;
   blink::WebGraphicsContext3D* createOffscreenGraphicsContext3D(
       const blink::WebGraphicsContext3D::Attributes& attributes,
       blink::WebGraphicsContext3D* share_context) override;
diff --git a/components/web_view/web_view_impl.cc b/components/web_view/web_view_impl.cc
index 6d140cb..e07f3cf 100644
--- a/components/web_view/web_view_impl.cc
+++ b/components/web_view/web_view_impl.cc
@@ -9,7 +9,6 @@
 
 #include "base/bind.h"
 #include "base/command_line.h"
-#include "components/devtools_service/public/cpp/switches.h"
 #include "components/mus/public/cpp/scoped_window_ptr.h"
 #include "components/mus/public/cpp/window.h"
 #include "components/mus/public/cpp/window_tree_connection.h"
@@ -26,14 +25,6 @@
 #include "url/gurl.h"
 
 namespace web_view {
-namespace {
-
-bool EnableRemoteDebugging() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      devtools_service::kRemoteDebuggingPort);
-}
-
-}  // namespace
 
 using web_view::mojom::ButtonState;
 
@@ -50,8 +41,7 @@ WebViewImpl::WebViewImpl(mojo::ApplicationImpl* app,
       content_(nullptr),
       find_controller_(this),
       navigation_controller_(this) {
-  if (EnableRemoteDebugging())
-    devtools_agent_.reset(new FrameDevToolsAgent(app_, this));
+  devtools_agent_.reset(new FrameDevToolsAgent(app_, this));
   OnDidNavigate();
 }
 
diff --git a/content/child/blink_platform_impl.cc b/content/child/blink_platform_impl.cc
index 0b7f0a7..1e4b72d 100644
--- a/content/child/blink_platform_impl.cc
+++ b/content/child/blink_platform_impl.cc
@@ -63,7 +63,6 @@
 #include "net/base/ip_address_number.h"
 #include "net/base/net_errors.h"
 #include "net/base/port_util.h"
-#include "third_party/WebKit/public/platform/WebConvertableToTraceFormat.h"
 #include "third_party/WebKit/public/platform/WebData.h"
 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
 #include "third_party/WebKit/public/platform/WebMemoryDumpProvider.h"
@@ -159,25 +158,6 @@ class MemoryUsageCache {
   base::Lock lock_;
 };
 
-class ConvertableToTraceFormatWrapper
-    : public base::trace_event::ConvertableToTraceFormat {
- public:
-  // We move a reference pointer from |convertable| to |convertable_|,
-  // rather than copying, for thread safety. https://crbug.com/478149
-  explicit ConvertableToTraceFormatWrapper(
-      blink::WebConvertableToTraceFormat& convertable) {
-    convertable_.moveFrom(convertable);
-  }
-  void AppendAsTraceFormat(std::string* out) const override {
-    *out += convertable_.asTraceFormat().utf8();
-  }
-
- private:
-  ~ConvertableToTraceFormatWrapper() override {}
-
-  blink::WebConvertableToTraceFormat convertable_;
-};
-
 }  // namespace
 
 static int ToMessageID(WebLocalizedString::Name name) {
@@ -634,81 +614,6 @@ void BlinkPlatformImpl::histogramSparse(const char* name, int sample) {
   UMA_HISTOGRAM_SPARSE_SLOWLY(name, sample);
 }
 
-const unsigned char* BlinkPlatformImpl::getTraceCategoryEnabledFlag(
-    const char* category_group) {
-  return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group);
-}
-
-blink::Platform::TraceEventAPIAtomicWord*
-BlinkPlatformImpl::getTraceSamplingState(const unsigned thread_bucket) {
-  switch (thread_bucket) {
-    case 0:
-      return reinterpret_cast<blink::Platform::TraceEventAPIAtomicWord*>(
-          &TRACE_EVENT_API_THREAD_BUCKET(0));
-    case 1:
-      return reinterpret_cast<blink::Platform::TraceEventAPIAtomicWord*>(
-          &TRACE_EVENT_API_THREAD_BUCKET(1));
-    case 2:
-      return reinterpret_cast<blink::Platform::TraceEventAPIAtomicWord*>(
-          &TRACE_EVENT_API_THREAD_BUCKET(2));
-    default:
-      NOTREACHED() << "Unknown thread bucket type.";
-  }
-  return NULL;
-}
-
-static_assert(
-    sizeof(blink::Platform::TraceEventHandle) ==
-        sizeof(base::trace_event::TraceEventHandle),
-    "TraceEventHandle types must be same size");
-
-blink::Platform::TraceEventHandle BlinkPlatformImpl::addTraceEvent(
-    char phase,
-    const unsigned char* category_group_enabled,
-    const char* name,
-    unsigned long long id,
-    unsigned long long bind_id,
-    double timestamp,
-    int num_args,
-    const char** arg_names,
-    const unsigned char* arg_types,
-    const unsigned long long* arg_values,
-    blink::WebConvertableToTraceFormat* convertable_values,
-    unsigned int flags) {
-  scoped_refptr<base::trace_event::ConvertableToTraceFormat>
-      convertable_wrappers[2];
-  if (convertable_values) {
-    size_t size = std::min(static_cast<size_t>(num_args),
-                           arraysize(convertable_wrappers));
-    for (size_t i = 0; i < size; ++i) {
-      if (arg_types[i] == TRACE_VALUE_TYPE_CONVERTABLE) {
-        convertable_wrappers[i] =
-            new ConvertableToTraceFormatWrapper(convertable_values[i]);
-      }
-    }
-  }
-  base::TimeTicks timestamp_tt =
-      base::TimeTicks() + base::TimeDelta::FromSecondsD(timestamp);
-  base::trace_event::TraceEventHandle handle =
-      TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
-          phase, category_group_enabled, name, id, bind_id,
-          base::PlatformThread::CurrentId(), timestamp_tt, num_args, arg_names,
-          arg_types, arg_values, convertable_wrappers, flags);
-  blink::Platform::TraceEventHandle result;
-  memcpy(&result, &handle, sizeof(result));
-  return result;
-}
-
-void BlinkPlatformImpl::updateTraceEventDuration(
-    const unsigned char* category_group_enabled,
-    const char* name,
-    TraceEventHandle handle) {
-  base::trace_event::TraceEventHandle traceEventHandle;
-  memcpy(&traceEventHandle, &handle, sizeof(handle));
-  TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
-      category_group_enabled, name, traceEventHandle);
-}
-
 void BlinkPlatformImpl::registerMemoryDumpProvider(
     blink::WebMemoryDumpProvider* wmdp, const char* name) {
   WebMemoryDumpProviderAdapter* wmdp_adapter =
diff --git a/content/child/blink_platform_impl.h b/content/child/blink_platform_impl.h
index ea44ffc..c245d4f 100644
--- a/content/child/blink_platform_impl.h
+++ b/content/child/blink_platform_impl.h
@@ -119,26 +119,6 @@ class CONTENT_EXPORT BlinkPlatformImpl
                             int sample,
                             int boundary_value) override;
   void histogramSparse(const char* name, int sample) override;
-  const unsigned char* getTraceCategoryEnabledFlag(
-      const char* category_name) override;
-  TraceEventAPIAtomicWord* getTraceSamplingState(
-      const unsigned thread_bucket) override;
-  TraceEventHandle addTraceEvent(
-      char phase,
-      const unsigned char* category_group_enabled,
-      const char* name,
-      unsigned long long id,
-      unsigned long long bind_id,
-      double timestamp,
-      int num_args,
-      const char** arg_names,
-      const unsigned char* arg_types,
-      const unsigned long long* arg_values,
-      blink::WebConvertableToTraceFormat* convertable_values,
-      unsigned int flags) override;
-  void updateTraceEventDuration(const unsigned char* category_group_enabled,
-                                const char* name,
-                                TraceEventHandle) override;
   void registerMemoryDumpProvider(blink::WebMemoryDumpProvider* wmdp,
                                   const char* name) override;
   void unregisterMemoryDumpProvider(
diff --git a/media/blink/run_all_unittests.cc b/media/blink/run_all_unittests.cc
index b3a946d..bcbc4e3 100644
--- a/media/blink/run_all_unittests.cc
+++ b/media/blink/run_all_unittests.cc
@@ -70,8 +70,6 @@ class TestBlinkPlatformSupport : NON_EXPORTED_BASE(public blink::Platform) {
  public:
   ~TestBlinkPlatformSupport() override;
 
-  const unsigned char* getTraceCategoryEnabledFlag(
-      const char* categoryName) override;
   blink::WebThread* currentThread() override { return &m_currentThread; }
 
  private:
@@ -80,12 +78,6 @@ class TestBlinkPlatformSupport : NON_EXPORTED_BASE(public blink::Platform) {
 
 TestBlinkPlatformSupport::~TestBlinkPlatformSupport() {}
 
-const unsigned char* TestBlinkPlatformSupport::getTraceCategoryEnabledFlag(
-    const char* categoryName) {
-  static const unsigned char tracingIsDisabled = 0;
-  return &tracingIsDisabled;
-}
-
 class BlinkMediaTestSuite : public base::TestSuite {
  public:
   BlinkMediaTestSuite(int argc, char** argv);
diff --git a/third_party/WebKit/Source/platform/EventTracer.cpp b/third_party/WebKit/Source/platform/EventTracer.cpp
index 30a8f11..08469ce 100644
--- a/third_party/WebKit/Source/platform/EventTracer.cpp
+++ b/third_party/WebKit/Source/platform/EventTracer.cpp
@@ -31,17 +31,45 @@
 #include "platform/EventTracer.h"
 
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "public/platform/Platform.h"
-#include "public/platform/WebConvertableToTraceFormat.h"
 #include "wtf/Assertions.h"
+#include "wtf/text/StringUTF8Adaptor.h"
 #include <stdio.h>
 
 namespace blink {
 
-static_assert(sizeof(Platform::TraceEventHandle) == sizeof(TraceEvent::TraceEventHandle), "TraceEventHandle types must be compatible");
-static_assert(sizeof(Platform::TraceEventAPIAtomicWord) == sizeof(TraceEvent::TraceEventAPIAtomicWord), "TraceEventAPIAtomicWord types must be compatible");
+static_assert(sizeof(TraceEvent::TraceEventHandle) == sizeof(base::trace_event::TraceEventHandle), "TraceEventHandle types must be the same");
 static_assert(sizeof(TraceEvent::TraceEventAPIAtomicWord) == sizeof(const char*), "TraceEventAPIAtomicWord must be pointer-sized.");
 
+namespace {
+
+class ConvertableToTraceFormatWrapper : public base::trace_event::ConvertableToTraceFormat {
+public:
+    // We move a reference pointer from |convertable| to |m_convertable|,
+    // rather than copying, for thread safety. https://crbug.com/478149
+    explicit ConvertableToTraceFormatWrapper(PassRefPtr<blink::TraceEvent::ConvertableToTraceFormat> convertable)
+        : m_convertable(convertable)
+    {
+        ASSERT(m_convertable);
+    }
+    void AppendAsTraceFormat(std::string* out) const override
+    {
+        // TODO(bashi): Avoid copying.
+        String traceFormat = m_convertable->asTraceFormat();
+        StringUTF8Adaptor utf8(traceFormat);
+        out->append(utf8.data(), utf8.length());
+    }
+    // TODO(bashi): Override EstimateTraceMemoryOverhead()
+
+private:
+    ~ConvertableToTraceFormatWrapper() override {}
+
+    RefPtr<blink::TraceEvent::ConvertableToTraceFormat> m_convertable;
+};
+
+} // namespace
+
 // The dummy variable is needed to avoid a crash when someone updates the state variables
 // before EventTracer::initialize() is called.
 TraceEvent::TraceEventAPIAtomicWord dummyTraceSamplingState = 0;
@@ -49,30 +77,21 @@ TraceEvent::TraceEventAPIAtomicWord* traceSamplingState[3] = {&dummyTraceSamplin
 
 void EventTracer::initialize()
 {
-    // current() might not exist in unit tests.
-    if (!Platform::current())
-        return;
-
-    traceSamplingState[0] = Platform::current()->getTraceSamplingState(0);
+    traceSamplingState[0] = reinterpret_cast<TraceEvent::TraceEventAPIAtomicWord*>(&TRACE_EVENT_API_THREAD_BUCKET(0));
     // FIXME: traceSamplingState[0] can be 0 in split-dll build. http://crbug.com/256965
     if (!traceSamplingState[0])
         traceSamplingState[0] = &dummyTraceSamplingState;
-    traceSamplingState[1] = Platform::current()->getTraceSamplingState(1);
+    traceSamplingState[1] = reinterpret_cast<TraceEvent::TraceEventAPIAtomicWord*>(&TRACE_EVENT_API_THREAD_BUCKET(1));
     if (!traceSamplingState[1])
         traceSamplingState[1] = &dummyTraceSamplingState;
-    traceSamplingState[2] = Platform::current()->getTraceSamplingState(2);
+    traceSamplingState[2] = reinterpret_cast<TraceEvent::TraceEventAPIAtomicWord*>(&TRACE_EVENT_API_THREAD_BUCKET(2));
     if (!traceSamplingState[2])
         traceSamplingState[2] = &dummyTraceSamplingState;
 }
 
 const unsigned char* EventTracer::getTraceCategoryEnabledFlag(const char* categoryName)
 {
-    static const char* dummyCategoryEnabledFlag = "*";
-    // current() might not exist in unit tests.
-    if (!Platform::current())
-        return reinterpret_cast<const unsigned char*>(dummyCategoryEnabledFlag);
-
-    return Platform::current()->getTraceCategoryEnabledFlag(categoryName);
+    return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(categoryName);
 }
 
 TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsigned char* categoryEnabledFlag,
@@ -83,10 +102,13 @@ TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsign
     PassRefPtr<TraceEvent::ConvertableToTraceFormat> convertableValue2,
     unsigned flags)
 {
-    WebConvertableToTraceFormat webConvertableValues[2];
-    webConvertableValues[0] = WebConvertableToTraceFormat(convertableValue1);
-    webConvertableValues[1] = WebConvertableToTraceFormat(convertableValue2);
-    return Platform::current()->addTraceEvent(phase, categoryEnabledFlag, name, id, bindId, timestamp, numArgs, argNames, argTypes, argValues, webConvertableValues, flags);
+    scoped_refptr<base::trace_event::ConvertableToTraceFormat> wrappers[2];
+    ASSERT(numArgs <= 2);
+    if (numArgs >= 1 && argTypes[0] == TRACE_VALUE_TYPE_CONVERTABLE)
+        wrappers[0] = new ConvertableToTraceFormatWrapper(convertableValue1);
+    if (numArgs >= 2 && argTypes[1] == TRACE_VALUE_TYPE_CONVERTABLE)
+        wrappers[1] = new ConvertableToTraceFormatWrapper(convertableValue2);
+    return addTraceEvent(phase, categoryEnabledFlag, name, id, bindId, timestamp, numArgs, argNames, argTypes, argValues, wrappers, flags);
 }
 
 TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsigned char* categoryEnabledFlag,
@@ -94,12 +116,26 @@ TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsign
     int numArgs, const char** argNames, const unsigned char* argTypes,
     const unsigned long long* argValues, unsigned flags)
 {
-    return Platform::current()->addTraceEvent(phase, categoryEnabledFlag, name, id, bindId, timestamp, numArgs, argNames, argTypes, argValues, 0, flags);
+    return addTraceEvent(phase, categoryEnabledFlag, name, id, bindId, timestamp, numArgs, argNames, argTypes, argValues, nullptr, flags);
+}
+
+TraceEvent::TraceEventHandle EventTracer::addTraceEvent(char phase, const unsigned char* categoryEnabledFlag,
+    const char* name, unsigned long long id, unsigned long long bindId, double timestamp,
+    int numArgs, const char** argNames, const unsigned char* argTypes, const unsigned long long* argValues,
+    const scoped_refptr<base::trace_event::ConvertableToTraceFormat>* convertables, unsigned flags)
+{
+    base::TimeTicks timestampTimeTicks = base::TimeTicks() + base::TimeDelta::FromSecondsD(timestamp);
+    base::trace_event::TraceEventHandle handle = TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(phase, categoryEnabledFlag, name, id, bindId, base::PlatformThread::CurrentId(), timestampTimeTicks, numArgs, argNames, argTypes, argValues, convertables, flags);
+    TraceEvent::TraceEventHandle result;
+    memcpy(&result, &handle, sizeof(result));
+    return result;
 }
 
 void EventTracer::updateTraceEventDuration(const unsigned char* categoryEnabledFlag, const char* name, TraceEvent::TraceEventHandle handle)
 {
-    Platform::current()->updateTraceEventDuration(categoryEnabledFlag, name, handle);
+    base::trace_event::TraceEventHandle traceEventHandle;
+    memcpy(&traceEventHandle, &handle, sizeof(handle));
+    TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(categoryEnabledFlag, name, traceEventHandle);
 }
 
 double EventTracer::systemTraceTime()
diff --git a/third_party/WebKit/Source/platform/EventTracer.h b/third_party/WebKit/Source/platform/EventTracer.h
index e6d4b4b..4b5ec04b 100644
--- a/third_party/WebKit/Source/platform/EventTracer.h
+++ b/third_party/WebKit/Source/platform/EventTracer.h
@@ -31,6 +31,7 @@
 #ifndef EventTracer_h
 #define EventTracer_h
 
+#include "base/memory/ref_counted.h"
 #include "platform/PlatformExport.h"
 #include "wtf/Allocator.h"
 #include "wtf/RefCounted.h"
@@ -39,6 +40,12 @@
 
 #include <stdint.h>
 
+namespace base {
+namespace trace_event {
+class ConvertableToTraceFormat;
+}
+}
+
 // This will mark the trace event as disabled by default. The user will need
 // to explicitly enable the event.
 #define TRACE_DISABLED_BY_DEFAULT(name) "disabled-by-default-" name
@@ -91,6 +98,20 @@ public:
         unsigned flags);
     static void updateTraceEventDuration(const unsigned char* categoryEnabledFlag, const char* name, TraceEvent::TraceEventHandle);
     static double systemTraceTime();
+
+private:
+    static TraceEvent::TraceEventHandle addTraceEvent(char phase,
+        const unsigned char* categoryEnabledFlag,
+        const char* name,
+        unsigned long long id,
+        unsigned long long bindId,
+        double timestamp,
+        int numArgs,
+        const char* argNames[],
+        const unsigned char argTypes[],
+        const unsigned long long argValues[],
+        const scoped_refptr<base::trace_event::ConvertableToTraceFormat>* convertables,
+        unsigned flags);
 };
 
 } // namespace blink
diff --git a/third_party/WebKit/Source/platform/blink_platform.gypi b/third_party/WebKit/Source/platform/blink_platform.gypi
index 49ea34b..9dec2b0 100644
--- a/third_party/WebKit/Source/platform/blink_platform.gypi
+++ b/third_party/WebKit/Source/platform/blink_platform.gypi
@@ -272,7 +272,6 @@
       'exported/WebContentDecryptionModuleResult.cpp',
       'exported/WebContentDecryptionModuleSession.cpp',
       'exported/WebContentSettingCallbacks.cpp',
-      'exported/WebConvertableToTraceFormat.cpp',
       'exported/WebCredential.cpp',
       'exported/WebCryptoAlgorithm.cpp',
       'exported/WebCryptoKey.cpp',
diff --git a/third_party/WebKit/Source/platform/exported/WebConvertableToTraceFormat.cpp b/third_party/WebKit/Source/platform/exported/WebConvertableToTraceFormat.cpp
deleted file mode 100644
index dca9367..0000000
--- a/third_party/WebKit/Source/platform/exported/WebConvertableToTraceFormat.cpp
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2014 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 "public/platform/WebConvertableToTraceFormat.h"
-
-#include "platform/EventTracer.h"
-#include "public/platform/WebString.h"
-
-namespace blink {
-
-WebConvertableToTraceFormat::WebConvertableToTraceFormat(PassRefPtr<TraceEvent::ConvertableToTraceFormat> convertable)
-    : m_private(convertable)
-{
-}
-
-WebString WebConvertableToTraceFormat::asTraceFormat() const
-{
-    return m_private->asTraceFormat();
-}
-
-void WebConvertableToTraceFormat::assign(const WebConvertableToTraceFormat& r)
-{
-    m_private = r.m_private;
-}
-
-void WebConvertableToTraceFormat::moveFrom(WebConvertableToTraceFormat& r)
-{
-    m_private.moveFrom(r.m_private);
-}
-
-void WebConvertableToTraceFormat::reset()
-{
-    m_private.reset();
-}
-
-} // namespace blink
diff --git a/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp b/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
index 928e88c..94c2e7c 100644
--- a/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
+++ b/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.cpp
@@ -89,12 +89,6 @@ WebDiscardableMemory* TestingPlatformSupport::allocateAndLockDiscardableMemory(s
     return !m_config.hasDiscardableMemorySupport ? 0 : new TestingDiscardableMemory(bytes);
 }
 
-const unsigned char* TestingPlatformSupport::getTraceCategoryEnabledFlag(const char* categoryName)
-{
-    static const unsigned char tracingIsDisabled = 0;
-    return &tracingIsDisabled;
-}
-
 WebString TestingPlatformSupport::defaultLocale()
 {
     return WebString::fromUTF8("en-US");
diff --git a/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.h b/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.h
index 027ed1d..fcaec86 100644
--- a/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.h
+++ b/third_party/WebKit/Source/platform/testing/TestingPlatformSupport.h
@@ -114,7 +114,6 @@ public:
 
     // Platform:
     WebDiscardableMemory* allocateAndLockDiscardableMemory(size_t bytes) override;
-    const unsigned char* getTraceCategoryEnabledFlag(const char* categoryName) override;
     WebString defaultLocale() override;
     WebCompositorSupport* compositorSupport() override;
     WebThread* currentThread() override;
diff --git a/third_party/WebKit/public/blink_headers.gypi b/third_party/WebKit/public/blink_headers.gypi
index fcb9d72..62f4b60 100644
--- a/third_party/WebKit/public/blink_headers.gypi
+++ b/third_party/WebKit/public/blink_headers.gypi
@@ -44,7 +44,6 @@
       "platform/WebContentLayer.h",
       "platform/WebContentLayerClient.h",
       "platform/WebContentSettingCallbacks.h",
-      "platform/WebConvertableToTraceFormat.h",
       "platform/WebCookieJar.h",
       "platform/WebCredential.h",
       "platform/WebCredentialManagerClient.h",
diff --git a/third_party/WebKit/public/platform/Platform.h b/third_party/WebKit/public/platform/Platform.h
index 166d149..bed866e 100644
--- a/third_party/WebKit/public/platform/Platform.h
+++ b/third_party/WebKit/public/platform/Platform.h
@@ -64,7 +64,6 @@ class WebBlobRegistry;
 class WebCanvasCaptureHandler;
 class WebClipboard;
 class WebCompositorSupport;
-class WebConvertableToTraceFormat;
 class WebCookieJar;
 class WebCrypto;
 class WebDatabaseObserver;
@@ -446,107 +445,6 @@ public:
     // Get a pointer to testing support interfaces. Will not be available in production builds.
     virtual WebUnitTestSupport* unitTestSupport() { return nullptr; }
 
-
-    // Tracing -------------------------------------------------------------
-
-    // Get a pointer to the enabled state of the given trace category. The
-    // embedder can dynamically change the enabled state as trace event
-    // recording is started and stopped by the application. Only long-lived
-    // literal strings should be given as the category name. The implementation
-    // expects the returned pointer to be held permanently in a local static. If
-    // the unsigned char is non-zero, tracing is enabled. If tracing is enabled,
-    // addTraceEvent is expected to be called by the trace event macros.
-    virtual const unsigned char* getTraceCategoryEnabledFlag(const char* categoryName) { return nullptr; }
-
-    typedef intptr_t TraceEventAPIAtomicWord;
-
-    // Get a pointer to a global state of the given thread. An embedder is
-    // expected to update the global state as the state of the embedder changes.
-    // A sampling thread in the Chromium side reads the global state periodically
-    // and reflects the sampling profiled results into about:tracing.
-    virtual TraceEventAPIAtomicWord* getTraceSamplingState(const unsigned bucketName) { return nullptr; }
-
-    typedef uint64_t TraceEventHandle;
-
-    // Add a trace event to the platform tracing system. Depending on the actual
-    // enabled state, this event may be recorded or dropped.
-    // - phase specifies the type of event:
-    //   - BEGIN ('B'): Marks the beginning of a scoped event.
-    //   - END ('E'): Marks the end of a scoped event.
-    //   - COMPLETE ('X'): Marks the beginning of a scoped event, but doesn't
-    //     need a matching END event. Instead, at the end of the scope,
-    //     updateTraceEventDuration() must be called with the TraceEventHandle
-    //     returned from addTraceEvent().
-    //   - INSTANT ('I'): Standalone, instantaneous event.
-    //   - START ('S'): Marks the beginning of an asynchronous event (the end
-    //     event can occur in a different scope or thread). The id parameter is
-    //     used to match START/FINISH pairs.
-    //   - FINISH ('F'): Marks the end of an asynchronous event.
-    //   - COUNTER ('C'): Used to trace integer quantities that change over
-    //     time. The argument values are expected to be of type int.
-    //   - METADATA ('M'): Reserved for internal use.
-    // - categoryEnabled is the pointer returned by getTraceCategoryEnabledFlag.
-    // - name is the name of the event. Also used to match BEGIN/END and
-    //   START/FINISH pairs.
-    // - id optionally allows events of the same name to be distinguished from
-    //   each other. For example, to trace the consutruction and destruction of
-    //   objects, specify the pointer as the id parameter.
-    // - numArgs specifies the number of elements in argNames, argTypes, and
-    //   argValues.
-    // - argNames is the array of argument names. Use long-lived literal strings
-    //   or specify the COPY flag.
-    // - argTypes is the array of argument types:
-    //   - BOOL (1): bool
-    //   - UINT (2): unsigned long long
-    //   - INT (3): long long
-    //   - DOUBLE (4): double
-    //   - POINTER (5): void*
-    //   - STRING (6): char* (long-lived null-terminated char* string)
-    //   - COPY_STRING (7): char* (temporary null-terminated char* string)
-    //   - CONVERTABLE (8): WebConvertableToTraceFormat
-    // - argValues is the array of argument values. Each value is the unsigned
-    //   long long member of a union of all supported types.
-    // - convertableValues is the array of WebConvertableToTraceFormat classes
-    //   that may be converted to trace format by calling asTraceFormat method.
-    //   ConvertableToTraceFormat interface.
-    //   convertableValues can be moved to another object by
-    //   WebConvertableToTraceFormat::moveFrom() in addTraceEvent(), and thus
-    //   should not be dereferenced (e.g. asTraceFormat() should not be called)
-    //   after return from addTraceEvent().
-    // - thresholdBeginId optionally specifies the value returned by a previous
-    //   call to addTraceEvent with a BEGIN phase.
-    // - threshold is used on an END phase event in conjunction with the
-    //   thresholdBeginId of a prior BEGIN event. The threshold is the minimum
-    //   number of microseconds that must have passed since the BEGIN event. If
-    //   less than threshold microseconds has passed, the BEGIN/END pair is
-    //   dropped.
-    // - flags can be 0 or one or more of the following, ORed together:
-    //   - COPY (0x1): treat all strings (name, argNames and argValues of type
-    //     string) as temporary so that they will be copied by addTraceEvent.
-    //   - HAS_ID (0x2): use the id argument to uniquely identify the event for
-    //     matching with other events of the same name.
-    //   - MANGLE_ID (0x4): specify this flag if the id parameter is the value
-    //     of a pointer.
-    virtual TraceEventHandle addTraceEvent(
-        char phase,
-        const unsigned char* categoryEnabledFlag,
-        const char* name,
-        unsigned long long id,
-        unsigned long long bindId,
-        double timestamp,
-        int numArgs,
-        const char** argNames,
-        const unsigned char* argTypes,
-        const unsigned long long* argValues,
-        WebConvertableToTraceFormat* convertableValues,
-        unsigned flags)
-    {
-        return 0;
-    }
-
-    // Set the duration field of a COMPLETE trace event.
-    virtual void updateTraceEventDuration(const unsigned char* categoryEnabledFlag, const char* name, TraceEventHandle) { }
-
     // Callbacks for reporting histogram data.
     // CustomCounts histogram has exponential bucket sizes, so that min=1, max=1000000, bucketCount=50 would do.
     virtual void histogramCustomCounts(const char* name, int sample, int min, int max, int bucketCount) { }
diff --git a/third_party/WebKit/public/platform/WebConvertableToTraceFormat.h b/third_party/WebKit/public/platform/WebConvertableToTraceFormat.h
deleted file mode 100644
index aaffa05..0000000
--- a/third_party/WebKit/public/platform/WebConvertableToTraceFormat.h
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright 2014 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.
-
-#ifndef WebConvertableToTraceFormat_h
-#define WebConvertableToTraceFormat_h
-
-#include "WebPrivatePtr.h"
-#include "WebString.h"
-
-namespace blink {
-
-namespace TraceEvent {
-class ConvertableToTraceFormat;
-}
-
-class WebConvertableToTraceFormat {
-public:
-    WebConvertableToTraceFormat() { }
-#if INSIDE_BLINK
-    WebConvertableToTraceFormat(PassRefPtr<TraceEvent::ConvertableToTraceFormat>);
-#endif
-    ~WebConvertableToTraceFormat() { reset(); }
-
-    BLINK_PLATFORM_EXPORT WebString asTraceFormat() const;
-    BLINK_PLATFORM_EXPORT void assign(const WebConvertableToTraceFormat&);
-    BLINK_PLATFORM_EXPORT void moveFrom(WebConvertableToTraceFormat&);
-    BLINK_PLATFORM_EXPORT void reset();
-
-    WebConvertableToTraceFormat(const WebConvertableToTraceFormat& r) { assign(r); }
-    WebConvertableToTraceFormat& operator=(const WebConvertableToTraceFormat& r)
-    {
-        assign(r);
-        return *this;
-    }
-
-private:
-    WebPrivatePtr<TraceEvent::ConvertableToTraceFormat> m_private;
-};
-
-} // namespace blink
-
-#endif