Coverity: Fix a few pass-by-values.

content/browser/gpu/gpu_data_manager_impl.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 "content/browser/gpu/gpu_data_manager_impl.h"
 
 #if defined(OS_MACOSX)
 #include <CoreGraphics/CGDisplayConfiguration.h>
 #endif
 
@@ skipping 258 matching lines @@
   }
   if (card_blacklisted_ ||
       command_line->HasSwitch(switches::kBlacklistWebGL)) {
     flags |= content::GPU_FEATURE_TYPE_WEBGL;
   }
   gpu_feature_type_ = static_cast<GpuFeatureType>(flags);
 
   EnableSoftwareRenderingIfNecessary();
 }
 
-void GpuDataManagerImpl::RegisterSwiftShaderPath(FilePath path) {
+void GpuDataManagerImpl::RegisterSwiftShaderPath(const FilePath& path) {
   swiftshader_path_ = path;
   EnableSoftwareRenderingIfNecessary();
 }
 
 const base::ListValue& GpuDataManagerImpl::GetLogMessages() const {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   return log_messages_;
 }
 
 void GpuDataManagerImpl::EnableSoftwareRenderingIfNecessary() {
@@ skipping 85 matching lines @@
 #if defined(OS_WIN)
     if (object->dx_diagnostics.values.size() == 0 &&
         object->dx_diagnostics.children.size() == 0) {
       object->dx_diagnostics = other.dx_diagnostics;
       changed = true;
     }
 #endif
   }
   return changed;
 }