Don't allow path traversal paths on the base file helpers

skia/ext/vector_canvas_unittest.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 "build/build_config.h"
 
 #if !defined(OS_WIN)
 #include <unistd.h>
 #endif
 
@@ skipping 316 matching lines @@
             (SkColorGetG(color) * 255 + alpha_offset) / alpha,
             (SkColorGetB(color) * 255 + alpha_offset) / alpha);
       }
     }
   }
 }
 
 void LoadPngFileToSkBitmap(const FilePath& filename,
                            SkBitmap* bitmap,
                            bool is_opaque) {
+  FilePath absolute_path(filename);
+  file_util::AbsolutePath(&absolute_path);
   std::string compressed;
-  file_util::ReadFileToString(filename, &compressed);
+  file_util::ReadFileToString(absolute_path, &compressed);
   ASSERT_TRUE(compressed.size());
 
   ASSERT_TRUE(gfx::PNGCodec::Decode(
       reinterpret_cast<const unsigned char*>(compressed.data()),
       compressed.size(), bitmap));
 
   EXPECT_EQ(is_opaque, bitmap->isOpaque());
   Premultiply(*bitmap);
 }
 
@@ skipping 611 matching lines @@
     pcanvas_->rotate(67);
     vcanvas_->drawBitmap(bitmap, 20, -50, NULL);
     pcanvas_->drawBitmap(bitmap, 20, -50, NULL);
     EXPECT_EQ(0., ProcessImage(FILE_PATH_LITERAL("rotate")));
   }
 }
 
 #endif  // !defined(USE_AURA)
 
 }  // namespace skia