Fix Visual Studio 2015 WebRtc x86 build.

webrtc/modules/audio_processing/transient/file_utils_unittest.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 401 matching lines @@
                  false,   // Write mode.
                  false,   // No loop.
                  false);  // No text.
   ASSERT_TRUE(file->Open()) << "File could not be opened:\n"
       << kOutFileName.c_str();
 
   const size_t kBufferLength = 3;
   rtc::scoped_ptr<float[]> written_buffer(new float[kBufferLength]);
   rtc::scoped_ptr<float[]> read_buffer(new float[kBufferLength]);
 
-  written_buffer[0] = kPi;
-  written_buffer[1] = kE;
-  written_buffer[2] = kAvogadro;
+  written_buffer[0] = static_cast<float>(kPi);
+  written_buffer[1] = static_cast<float>(kE);
+  written_buffer[2] = static_cast<float>(kAvogadro);
 
   EXPECT_EQ(kBufferLength, WriteFloatBufferToFile(file.get(),
                                                   kBufferLength,
                                                   written_buffer.get()));
 
   file->CloseFile();
 
   file->OpenFile(kOutFileName.c_str(),
                  true,    // Read only.
                  false,   // No loop.
@@ skipping 108 matching lines @@
   EXPECT_EQ(0u, WriteInt16BufferToFile(file.get(), 1, NULL));
   EXPECT_EQ(0u, WriteInt16BufferToFile(file.get(), 0, int16_buffer.get()));
 
   EXPECT_EQ(0u, WriteDoubleBufferToFile(NULL, 1, double_buffer.get()));
   EXPECT_EQ(0u, WriteDoubleBufferToFile(file.get(), 1, NULL));
   EXPECT_EQ(0u, WriteDoubleBufferToFile(file.get(), 0, double_buffer.get()));
 }
 
 }  // namespace webrtc