[chromedriver] Use percentFull instead of value in Tracing.bufferUsage.

chrome/test/chromedriver/performance_logger.cc

 // 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 "chrome/test/chromedriver/performance_logger.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 181 matching lines @@
     for (const auto& trace : *traces) {
       base::DictionaryValue* event_dict;
       if (!trace->GetAsDictionary(&event_dict))
         return Status(kUnknownError, "trace event must be a dictionary");
       AddLogEntry(client->GetId(), "Tracing.dataCollected", *event_dict);
     }
   } else if (method == "Tracing.bufferUsage") {
     // 'value' will be between 0-1 and represents how full the DevTools trace
     // buffer is. If the buffer is full, warn the user.
     double buffer_usage = 0;
-    if (!params.GetDouble("value", &buffer_usage)) {
+    if (!params.GetDouble("percentFull", &buffer_usage)) {
       // Tracing.bufferUsage event will occur once per second, and it really
       // only serves as a warning, so if we can't reliably tell whether the
       // buffer is full, just fail silently instead of spamming the logs.
       return Status(kOk);
     }
     if (buffer_usage >= 0.99999) {
       base::DictionaryValue params;
       std::string err("Chrome's trace buffer filled while collecting events, "
                       "so some trace events may have been lost");
       params.SetString("error", err);
@@ skipping 74 matching lines @@
   if (status.IsError())
     return status;
 
   return StartTrace();
 }
 
 Status PerformanceLogger::IsTraceDone(bool* trace_done) const {
   *trace_done = !trace_buffering_;
   return Status(kOk);
 }