int16<->float conversions: Use size_t for array length argument, not int

size_t is more appropriate for array lengths, since int might
theoretically be too small for a really large array. But more
importantly, if the caller's value is naturally of type size_t and the
function requires an int, VC++ will trigger warning C4267
(http://msdn.microsoft.com/en-us/library/6kck0s93.aspx) because the
implicit cast might be lossy, forcing the caller to do a manual cast.
Typing the function with size_t in the first place resolves the
problem.

R=aluebs@webrtc.org, andrew@webrtc.org, minyue@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/21909004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6702 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/common_audio/audio_util.cc b/webrtc/common_audio/audio_util.cc
index 0c961e1..f2936b0 100644
--- a/webrtc/common_audio/audio_util.cc
+++ b/webrtc/common_audio/audio_util.cc
@@ -14,18 +14,18 @@
 
 namespace webrtc {
 
-void RoundToInt16(const float* src, int size, int16_t* dest) {
-  for (int i = 0; i < size; ++i)
+void RoundToInt16(const float* src, size_t size, int16_t* dest) {
+  for (size_t i = 0; i < size; ++i)
     dest[i] = RoundToInt16(src[i]);
 }
 
-void ScaleAndRoundToInt16(const float* src, int size, int16_t* dest) {
-  for (int i = 0; i < size; ++i)
+void ScaleAndRoundToInt16(const float* src, size_t size, int16_t* dest) {
+  for (size_t i = 0; i < size; ++i)
     dest[i] = ScaleAndRoundToInt16(src[i]);
 }
 
-void ScaleToFloat(const int16_t* src, int size, float* dest) {
-  for (int i = 0; i < size; ++i)
+void ScaleToFloat(const int16_t* src, size_t size, float* dest) {
+  for (size_t i = 0; i < size; ++i)
     dest[i] = ScaleToFloat(src[i]);
 }
 
diff --git a/webrtc/common_audio/include/audio_util.h b/webrtc/common_audio/include/audio_util.h
index 18fdbe2..9972a0e 100644
--- a/webrtc/common_audio/include/audio_util.h
+++ b/webrtc/common_audio/include/audio_util.h
@@ -47,14 +47,14 @@
 }
 
 // Round |size| elements of |src| to int16 with clamping and write to |dest|.
-void RoundToInt16(const float* src, int size, int16_t* dest);
+void RoundToInt16(const float* src, size_t size, int16_t* dest);
 
 // Scale (from [-1, 1]) and round |size| elements of |src| to full-range int16
 // with clamping and write to |dest|.
-void ScaleAndRoundToInt16(const float* src, int size, int16_t* dest);
+void ScaleAndRoundToInt16(const float* src, size_t size, int16_t* dest);
 
 // Scale |size| elements of |src| to float [-1, 1] and write to |dest|.
-void ScaleToFloat(const int16_t* src, int size, float* dest);
+void ScaleToFloat(const int16_t* src, size_t size, float* dest);
 
 // Deinterleave audio from |interleaved| to the channel buffers pointed to
 // by |deinterleaved|. There must be sufficient space allocated in the