Update GPU memory buffers to use StrideInBytes internally.

content/common/gpu/gpu_memory_buffer_factory_shared_memory.cc

Index: content/common/gpu/gpu_memory_buffer_factory_shared_memory.cc
diff --git a/content/common/gpu/gpu_memory_buffer_factory_shared_memory.cc b/content/common/gpu/gpu_memory_buffer_factory_shared_memory.cc
index 9a4bdcf538cab2132266fe8de6202c1f1e7be133..ea9ebb19308786e40c9de71673f98b37af272ab2 100644
--- a/content/common/gpu/gpu_memory_buffer_factory_shared_memory.cc
+++ b/content/common/gpu/gpu_memory_buffer_factory_shared_memory.cc
@@ -39,7 +39,7 @@ GpuMemoryBufferFactorySharedMemory::CreateGpuMemoryBuffer(
     gfx::PluginWindowHandle surface_handle) {
   base::SharedMemory shared_memory;
   if (!shared_memory.CreateAnonymous(
-          size.GetArea() * GpuMemoryBufferImpl::BytesPerPixel(format)))
+          GpuMemoryBufferImpl::PixelsToBytes(size.GetArea(), format)))
     return gfx::GpuMemoryBufferHandle();
 
   gfx::GpuMemoryBufferHandle handle;