gfx: Use unsigned strides for gpu memory buffers.

gpu/ipc/client/gpu_memory_buffer_impl_surface_texture.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/ipc/client/gpu_memory_buffer_impl_surface_texture.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/trace_event/trace_event.h"
 #include "gpu/ipc/common/android/surface_texture_manager.h"
@@ skipping 117 matching lines @@
   return buffer_.bits;
 }
 
 void GpuMemoryBufferImplSurfaceTexture::Unmap() {
   TRACE_EVENT0("gpu", "GpuMemoryBufferImplSurfaceTexture::Unmap");
   DCHECK(mapped_);
   ANativeWindow_unlockAndPost(native_window_);
   mapped_ = false;
 }
 
-int GpuMemoryBufferImplSurfaceTexture::stride(size_t plane) const {
+uint32_t GpuMemoryBufferImplSurfaceTexture::stride(size_t plane) const {
   DCHECK(mapped_);
   DCHECK_EQ(0u, plane);
   return gfx::RowSizeForBufferFormat(buffer_.stride, format_, 0);
 }
 
 gfx::GpuMemoryBufferHandle GpuMemoryBufferImplSurfaceTexture::GetHandle()
     const {
   gfx::GpuMemoryBufferHandle handle;
   handle.type = gfx::SURFACE_TEXTURE_BUFFER;
   handle.id = id_;
   return handle;
 }
 
 }  // namespace gpu