enable unused parameter warning

android.mk builds have unused parameter warning on by default.
This change for GN makes libyuv build the same way.

BUG=libyuv:681
TEST=build on linux with clang and ninja.

Change-Id: I76c627d446b96653f147725bca915d94a42ce9a6
Reviewed-on: https://chromium-review.googlesource.com/441194Reviewed-by: Frank Barchard <fbarchard@google.com>
Commit-Queue: Frank Barchard <fbarchard@google.com>

source/cpu_id.cc

@@ -95,6 +95,8 @@ void CpuId(uint32 info_eax, uint32 info_ecx, uint32* cpu_info) {
 #else  // (defined(_M_IX86) || defined(_M_X64) ...
 LIBYUV_API
 void CpuId(uint32 eax, uint32 ecx, uint32* cpu_info) {
+  (void)eax;
+  (void)ecx;
   cpu_info[0] = cpu_info[1] = cpu_info[2] = cpu_info[3] = 0;
 }
 #endif

unit_test/planar_test.cc

@@ -1173,12 +1173,12 @@ static void TestBlendPlane(int width,
   MaskCpuFlags(disable_cpu_flags);
   BlendPlane(src_argb_a + off, width, src_argb_b + off, width,
              src_argb_alpha + off, width, dst_argb_c + off, width, width,
-             height);
+             invert * height);
   MaskCpuFlags(benchmark_cpu_info);
   for (int i = 0; i < benchmark_iterations; ++i) {
     BlendPlane(src_argb_a + off, width, src_argb_b + off, width,
                src_argb_alpha + off, width, dst_argb_opt + off, width, width,
-               height);
+               invert * height);
   }
   for (int i = 0; i < kStride * height; ++i) {
     EXPECT_EQ(dst_argb_c[i + off], dst_argb_opt[i + off]);
@@ -1252,14 +1252,15 @@ static void TestI420Blend(int width,
   I420Blend(src_y0 + off, width, src_u0 + off, kStrideUV, src_v0 + off,
             kStrideUV, src_y1 + off, width, src_u1 + off, kStrideUV,
             src_v1 + off, kStrideUV, src_a + off, width, dst_y_c + off, width,
-            dst_u_c + off, kStrideUV, dst_v_c + off, kStrideUV, width, height);
+            dst_u_c + off, kStrideUV, dst_v_c + off, kStrideUV, width,
+            invert * height);
   MaskCpuFlags(benchmark_cpu_info);
   for (int i = 0; i < benchmark_iterations; ++i) {
     I420Blend(src_y0 + off, width, src_u0 + off, kStrideUV, src_v0 + off,
               kStrideUV, src_y1 + off, width, src_u1 + off, kStrideUV,
               src_v1 + off, kStrideUV, src_a + off, width, dst_y_opt + off,
               width, dst_u_opt + off, kStrideUV, dst_v_opt + off, kStrideUV,
-              width, height);
+              width, invert * height);
   }
   for (int i = 0; i < width * height; ++i) {
     EXPECT_EQ(dst_y_c[i + off], dst_y_opt[i + off]);