initialize cpu flags to fix compile error on windows

R=harryjin@google.com
BUG=libyuv:512

Review URL: https://codereview.chromium.org/1422733003 .

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1520
+Version: 1521
 License: BSD
 License File: LICENSE
 

include/libyuv/cpu_id.h

@@ -37,6 +37,7 @@ static const int kCpuHasAVX = 0x200;
 static const int kCpuHasAVX2 = 0x400;
 static const int kCpuHasERMS = 0x800;
 static const int kCpuHasFMA3 = 0x1000;
+static const int kCpuHasAVX3 = 0x2000;  // TODO(fbarchard): implement detect.
 // 0x2000, 0x4000, 0x8000 reserved for future X86 flags.
 
 // These flags are only valid on MIPS processors.

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1520
+#define LIBYUV_VERSION 1521
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/cpu_id.cc

@@ -197,7 +197,8 @@ static LIBYUV_BOOL TestEnv(const char*) {
 
 LIBYUV_API SAFEBUFFERS
 int InitCpuFlags(void) {
-  int cpu_info;
+  // TODO(fbarchard): swap kCpuInit logic so 0 means uninitialized.
+  int cpu_info = 0;
 #if !defined(__pnacl__) && !defined(__CLR_VER) && defined(CPU_X86)
   uint32 cpu_info0[4] = { 0, 0, 0, 0 };
   uint32 cpu_info1[4] = { 0, 0, 0, 0 };