Use proper tracing category in image/tab capture trace logs

chrome/browser/extensions/api/tab_capture/tab_capture_performancetest.cc

 // Copyright 2013 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 "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/strings/stringprintf.h"
 #include "base/test/trace_event_analyzer.h"
 #include "base/win/windows_version.h"
 #include "chrome/browser/extensions/extension_apitest.h"
@@ skipping 163 matching lines @@
 
   void RunTest(const std::string& test_name) {
     if (HasFlag(kUseGpu) && !IsGpuAvailable()) {
       LOG(WARNING) <<
           "Test skipped: requires gpu. Pass --enable-gpu on the command "
           "line if use of GPU is desired.";
       return;
     }
 
     std::string json_events;
-    ASSERT_TRUE(tracing::BeginTracing("gpu,mirroring"));
+    ASSERT_TRUE(tracing::BeginTracing("gpu,gpu.capture"));
     std::string page = "performance.html";
     page += HasFlag(kTestThroughWebRTC) ? "?WebRTC=1" : "?WebRTC=0";
     // Ideally we'd like to run a higher capture rate when vsync is disabled,
     // but libjingle currently doesn't allow that.
     // page += HasFlag(kDisableVsync) ? "&fps=300" : "&fps=30";
     page += "&fps=30";
     ASSERT_TRUE(RunExtensionSubtest("tab_capture", page)) << message_;
     ASSERT_TRUE(tracing::EndTracing(&json_events));
     scoped_ptr<trace_analyzer::TraceAnalyzer> analyzer;
     analyzer.reset(trace_analyzer::TraceAnalyzer::Create(json_events));
@@ skipping 52 matching lines @@
     TabCapturePerformanceTest,
     testing::Values(
         kScalingTestBase | kScaleQualityFast,
         kScalingTestBase | kScaleQualityGood,
         kScalingTestBase | kScaleQualityBest,
         kScalingTestBase | kScaleQualityFast | kSmallWindow,
         kScalingTestBase | kScaleQualityGood | kSmallWindow,
         kScalingTestBase | kScaleQualityBest | kSmallWindow));
 
 #endif  // USE_AURA