gfx: Use unsigned strides for gpu memory buffers.

services/ui/public/cpp/mojo_gpu_memory_buffer.h

 // Copyright 2015 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.
 
 #ifndef SERVICES_UI_PUBLIC_CPP_MOJO_GPU_MEMORY_BUFFER_H_
 #define SERVICES_UI_PUBLIC_CPP_MOJO_GPU_MEMORY_BUFFER_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 18 matching lines @@
       gfx::BufferFormat format,
       gfx::BufferUsage usage);
   static MojoGpuMemoryBufferImpl* FromClientBuffer(ClientBuffer buffer);
 
   const unsigned char* GetMemory() const;
 
   // Overridden from gfx::GpuMemoryBuffer:
   bool Map() override;
   void* memory(size_t plane) override;
   void Unmap() override;
-  int stride(size_t plane) const override;
+  uint32_t stride(size_t plane) const override;
   gfx::GpuMemoryBufferHandle GetHandle() const override;
 
   // Overridden from gfx::GpuMemoryBufferImpl
   gfx::GpuMemoryBufferType GetBufferType() const override;
 
  private:
   MojoGpuMemoryBufferImpl(const gfx::Size& size,
                           gfx::BufferFormat format,
                           std::unique_ptr<base::SharedMemory> shared_memory,
                           uint32_t offset,
-                          int32_t stride);
+                          uint32_t stride);
 
   std::unique_ptr<base::SharedMemory> shared_memory_;
   const uint32_t offset_;
-  const int32_t stride_;
+  const uint32_t stride_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoGpuMemoryBufferImpl);
 };
 
 }  // namespace ui
 
 #endif  // SERVICES_UI_PUBLIC_CPP_MOJO_GPU_MEMORY_BUFFER_H_