linux: Cache GetFontRenderParams() results.

ui/gfx/font_render_params_linux_unittest.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 "ui/gfx/font_render_params.h"
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/macros.h"
@@ skipping 49 matching lines @@
 
 }  // namespace
 
 class FontRenderParamsTest : public testing::Test {
  public:
   FontRenderParamsTest() {
     SetUpFontconfig();
     CHECK(temp_dir_.CreateUniqueTempDir());
     original_font_delegate_ = LinuxFontDelegate::instance();
     LinuxFontDelegate::SetInstance(&test_font_delegate_);
+    ClearFontRenderParamsCacheForTest();
   }
 
   virtual ~FontRenderParamsTest() {
     LinuxFontDelegate::SetInstance(
         const_cast<LinuxFontDelegate*>(original_font_delegate_));
     TearDownFontconfig();
   }
 
  protected:
   base::ScopedTempDir temp_dir_;
@@ skipping 271 matching lines @@
   EXPECT_EQ("Verdana", suggested_family);
 
   query.families.clear();
   query.families.push_back("Arial");
   suggested_family.clear();
   GetFontRenderParams(query, &suggested_family);
   EXPECT_EQ("Verdana", suggested_family);
 }
 
 }  // namespace gfx