switch cpu flags to 0 for unitialized to avoid compare

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

Review URL: https://codereview.chromium.org/1418253002 .

DEPS

@@ -7,7 +7,7 @@ vars = {
 
   # Roll the Chromium Git hash to pick up newer versions of all the
   # dependencies and tools linked to in setup_links.py.
-  'chromium_revision': '5979bb6a5e5a298a2625693580925868cdf24ddb',
+  'chromium_revision': 'ec6107434ebf366554bb2af162d602ff34d480c1',
 }
 
 # NOTE: Prefer revision numbers to tags for svn deps. Use http rather than

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1521
+Version: 1522
 License: BSD
 License File: LICENSE
 

include/libyuv/cpu_id.h

@@ -18,9 +18,8 @@ namespace libyuv {
 extern "C" {
 #endif
 
-// TODO(fbarchard): Consider overlapping bits for different architectures.
 // Internal flag to indicate cpuid requires initialization.
-#define kCpuInit 0x1
+static const int kCpuInitialized = 0x1;
 
 // These flags are only valid on ARM processors.
 static const int kCpuHasARM = 0x2;
@@ -58,7 +57,7 @@ int ArmCpuCaps(const char* cpuinfo_name);
 // returns non-zero if instruction set is detected
 static __inline int TestCpuFlag(int test_flag) {
   LIBYUV_API extern int cpu_info_;
-  return (cpu_info_ == kCpuInit ? InitCpuFlags() : cpu_info_) & test_flag;
+  return (!cpu_info_ ? InitCpuFlags() : cpu_info_) & test_flag;
 }
 
 // For testing, allow CPU flags to be disabled.

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1521
+#define LIBYUV_VERSION 1522
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/cpu_id.cc

@@ -174,7 +174,7 @@ static int MipsCpuCaps(const char* search_string) {
 
 // CPU detect function for SIMD instruction sets.
 LIBYUV_API
-int cpu_info_ = kCpuInit;  // cpu_info is not initialized yet.
+int cpu_info_ = 0;  // cpu_info is not initialized yet.
 
 // Test environment variable for disabling CPU features. Any non-zero value
 // to disable. Zero ignored to make it easy to set the variable on/off.
@@ -291,8 +291,9 @@ int InitCpuFlags(void) {
   if (TestEnv("LIBYUV_DISABLE_ASM")) {
     cpu_info = 0;
   }
+  cpu_info  |= kCpuInitialized;
   cpu_info_ = cpu_info;
-  return cpu_info_;
+  return cpu_info;
 }
 
 // Note that use of this function is not thread safe.