Fix Visual Studio 2015 WebRtc x86 build.

webrtc/modules/audio_processing/transient/file_utils_unittest.cc

Index: webrtc/modules/audio_processing/transient/file_utils_unittest.cc
diff --git a/webrtc/modules/audio_processing/transient/file_utils_unittest.cc b/webrtc/modules/audio_processing/transient/file_utils_unittest.cc
index 7a035d2b41fbef15ced06bc5ab7ea382084e9aa8..48f3f43fdd13c46a671d18a960311705d6831e8f 100644
--- a/webrtc/modules/audio_processing/transient/file_utils_unittest.cc
+++ b/webrtc/modules/audio_processing/transient/file_utils_unittest.cc
@@ -365,9 +365,9 @@ TEST_F(TransientFileUtilsTest, DISABLED_ON_IOS(WriteFloatBufferToFile)) {
   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,