Don't log GPU blackluist stats if GPU blacklist is not loaded.

chrome/browser/gpu_util.cc

 // Copyright (c) 2012 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/browser/gpu_util.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 372 matching lines @@
     dx_info = DxDiagNodeToList(gpu_info.dx_diagnostics);
   else
     dx_info = Value::CreateNullValue();
   info->Set("diagnostics", dx_info);
 #endif
 
   return info;
 }
 
 void UpdateStats() {
+  GpuBlacklist* blacklist = GpuBlacklist::GetInstance();
+  uint32 max_entry_id = blacklist->max_entry_id();
+  if (max_entry_id == 0) {
+    // GPU Blacklist was not loaded.  No need to go further.
+    return;
+  }
+
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   uint32 flags = GpuDataManager::GetInstance()->GetGpuFeatureType();
-  GpuBlacklist* blacklist = GpuBlacklist::GetInstance();
   bool disabled = false;
   if (flags == 0) {
     UMA_HISTOGRAM_ENUMERATION("GPU.BlacklistTestResultsPerEntry",
-        0, blacklist->max_entry_id() + 1);
+        0, max_entry_id + 1);
   } else {
     std::vector<uint32> flag_entries;
     blacklist->GetGpuFeatureTypeEntries(
         content::GPU_FEATURE_TYPE_ALL, flag_entries, disabled);
     DCHECK_GT(flag_entries.size(), 0u);
     for (size_t i = 0; i < flag_entries.size(); ++i) {
       UMA_HISTOGRAM_ENUMERATION("GPU.BlacklistTestResultsPerEntry",
-          flag_entries[i], blacklist->max_entry_id() + 1);
+          flag_entries[i], max_entry_id + 1);
     }
   }
 
   // This counts how many users are affected by a disabled entry - this allows
   // us to understand the impact of an entry before enable it.
   std::vector<uint32> flag_disabled_entries;
   disabled = true;
   blacklist->GetGpuFeatureTypeEntries(
       content::GPU_FEATURE_TYPE_ALL, flag_disabled_entries, disabled);
   for (size_t i = 0; i < flag_disabled_entries.size(); ++i) {
     UMA_HISTOGRAM_ENUMERATION("GPU.BlacklistTestResultsPerDisabledEntry",
-        flag_disabled_entries[i], blacklist->max_entry_id() + 1);
+        flag_disabled_entries[i], max_entry_id + 1);
   }
 
   const content::GpuFeatureType kGpuFeatures[] = {
       content::GPU_FEATURE_TYPE_ACCELERATED_2D_CANVAS,
       content::GPU_FEATURE_TYPE_ACCELERATED_COMPOSITING,
       content::GPU_FEATURE_TYPE_WEBGL
   };
   const std::string kGpuBlacklistFeatureHistogramNames[] = {
       "GPU.BlacklistFeatureTestResults.Accelerated2dCanvas",
       "GPU.BlacklistFeatureTestResults.AcceleratedCompositing",
@@ skipping 31 matching lines @@
         kGpuBlacklistFeatureHistogramNamesWin[i],
         1, kNumWinSubVersions * kGpuFeatureNumStatus,
         kNumWinSubVersions * kGpuFeatureNumStatus + 1,
         base::Histogram::kUmaTargetedHistogramFlag);
     histogram_pointer->Add(GetGpuBlacklistHistogramValueWin(value));
 #endif
   }
 }
 
 }  // namespace gpu_util;