Update GPU memory buffers to use StrideInBytes internally.

content/common/gpu/client/gpu_memory_buffer_impl_unittest.cc

Index: content/common/gpu/client/gpu_memory_buffer_impl_unittest.cc
diff --git a/content/common/gpu/client/gpu_memory_buffer_impl_unittest.cc b/content/common/gpu/client/gpu_memory_buffer_impl_unittest.cc
index 3ac1b8329cad7ee1a8c61a0d5a9a296149384d95..8ca0e7040664f54e39e6dee60e8cba2ad19b81a6 100644
--- a/content/common/gpu/client/gpu_memory_buffer_impl_unittest.cc
+++ b/content/common/gpu/client/gpu_memory_buffer_impl_unittest.cc
@@ -86,9 +86,8 @@ TEST_P(GpuMemoryBufferImplTest, Map) {
     if (configuration.usage != gfx::GpuMemoryBuffer::MAP)
       continue;
 
-    size_t width_in_bytes =
-        GpuMemoryBufferImpl::BytesPerPixel(configuration.format) *
-        buffer_size.width();
+    size_t width_in_bytes = GpuMemoryBufferImpl::PixelsToBytes(
+        buffer_size.width(), configuration.format);
     EXPECT_GT(width_in_bytes, 0u);
     scoped_ptr<char[]> data(new char[width_in_bytes]);
     memset(data.get(), 0x2a, width_in_bytes);