Speed up rounding to byte test

R=harryjin@google.com
BUG=libyuv:492

Review URL: https://codereview.chromium.org/1367403007 .

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1497
+Version: 1499
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1497
+#define LIBYUV_VERSION 1499
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

unit_test/color_test.cc

@@ -223,13 +223,13 @@ static void YJToRGB(int y, int* r, int* g, int* b) {
 }
 
 // Pick a method for clamping.
-#define CLAMPMETHOD_IF 1
+//  #define CLAMPMETHOD_IF 1
 //  #define CLAMPMETHOD_TABLE 1
-//  #define CLAMPMETHOD_TERNARY 1
+#define CLAMPMETHOD_TERNARY 1
 //  #define CLAMPMETHOD_MASK 1
 
 // Pick a method for rounding.
-#define ROUND(f) static_cast<int>(f + 0.5)
+#define ROUND(f) static_cast<int>(f + 0.5f)
 //  #define ROUND(f) lrintf(f)
 //  #define ROUND(f) static_cast<int>(round(f))
 //  #define ROUND(f) _mm_cvt_ss2si(_mm_load_ss(&f))
@@ -314,17 +314,15 @@ static int RoundToByte(float f) {
 
 TEST_F(libyuvTest, TestRoundToByte) {
   int allb = 0;
+  int count = benchmark_width_ * benchmark_height_;
   for (int i = 0; i < benchmark_iterations_; ++i) {
-    for (int u2 = 0; u2 < 256; ++u2) {
-      for (int v2 = 0; v2 < 256; ++v2) {
-        for (int y2 = 0; y2 < 256; ++y2) {
-          int y = RANDOM256(y2);
-          int b = RoundToByte(y * 810.33 - 257);
+    float f = (fastrand() & 255) * 3.14f - 260.f;
+    for (int j = 0; j < count; ++j) {
+      int b = RoundToByte(f);
+      f += 0.91f;
       allb |= b;
     }
   }
-    }
-  }
   EXPECT_GE(allb, 0);
   EXPECT_LE(allb, 255);
 }